The best first mods for a 1999-2004 New Edge Mustang are lowering springs with matched shocks and struts, a cold air intake, a cat-back exhaust, and 3.73 or 4.10 rear gears. Those four changes fix the car's biggest stock weaknesses (ride height, sound, airflow and gearing) for the least money. Wheels and tires, tubular rear control arms, headers with a mid-pipe, a throttle body and plenum, and a short-throw shifter come next.
The New Edge is now more than 25 years old, and many have already been modified. I've owned four New Edge Mustangs, all 2004 models: three GTs and a V6. One GT was the Competition Orange car that later became LMR's Project Keeping Comp restoration. Another was a silver GT, and in high school I drove a Performance Red GT convertible. I've also owned a 1988 Mustang GT convertible. This guide covers what I'd change first on a stock car, why each part works, and the order that gets the most out of your budget. Look for the "From my garage" notes under each mod for what actually happened on my cars.
The 1999 facelift of the SN95 Mustang brought sharper "New Edge" styling and a big jump in power for the GT. Its 4.6L 2-valve V8 gained Performance Improved (PI) cylinder heads and a new intake, taking output from 225 hp in 1998 to 260 hp. The car still rides on the Fox-derived platform, so it shares a deep aftermarket with earlier Mustangs.
| Model | Years | Engine | Rated Power | Notes |
| V6 | 1999-2004 | 3.8L V6 (3.9L in 2004) | 190-193 hp | Solid axle, 7.5-inch |
| GT | 1999-2004 | 4.6L SOHC 2V V8 | 260 hp | Solid axle, 8.8-inch |
| Bullitt | 2001 | 4.6L SOHC 2V V8 | 265 hp | Solid axle, 8.8-inch |
| Mach 1 | 2003-2004 | 4.6L SOHC 4V V8 | 305 hp | Solid axle, 8.8-inch |
| SVT Cobra | 1999, 2001 | 4.6L SOHC 4V V8 | 320 hp | Independent (IRS) |
| SVT Cobra | 2003-2004 | Supercharged 4.6L DOHC 4V V8 | 390 hp | Independent (IRS) |
GT manual cars used the T-45 five-speed through 2000 and the TR-3650 from 2001; automatics used the 4R70W. Fitment differs by model, so check the year, body and engine on every part before you order. The rear control arm advice below applies to solid-axle cars only; IRS Cobras use different rear suspension parts.
The 10 Best First Mods For a New Edge Mustang
1. Lowering Springs With Matched Shocks & Struts
Lowering springs are the single biggest visual fix for a stock New Edge, which sits high from the factory. A drop of about 2 inches suits the 1999-2004 body and lowers the center of gravity for flatter cornering. LMR carries springs from mild to aggressive drops, including SVE lowering springs.
Replace the factory shocks and struts at the same time. Lowering the car moves the shock piston deeper into its stroke, and stock valving is not built for that position. Shocks and struts designed for lowered cars keep the ride controlled and reduce bottoming. Plan for an alignment after install, and consider caster/camber plates on bigger drops.
From my garage: On each of my vehicles, I ran SVE lowering springs with either Tokico or KYB struts. I chose the SVE springs due to their affordability, mid-level drop, and comfort. I road raced my Comp Orange car on the SVE Springs and Tokicos
2. Cold Air Intake
A cold air intake (CAI) replaces the restrictive stock airbox and feeds the engine cooler, denser air, which makes more power. On the New Edge, a fenderwell-style CAI places the filter inside the fender, away from engine bay heat, for the coolest air charge. Kits are available from BBK, JLT, K&N and others.
From my garage: For cold air intakes, I usually ran a BBK cold air intake, but have also run a more affordable cold air intake as I did not feel a big difference in performance for the extra cost.
3. Cat-back Exhaust
A cat-back exhaust is the most popular first mod because it changes the car's sound and look in one bolt-on install. It replaces everything behind the catalytic converters with larger-diameter tubing and new mufflers and tips. Swapping mufflers alone requires cutting and welding and costs nearly as much, so a full cat-back is usually the better value.
Muffler design sets the tone. Chambered mufflers such as Flowmaster sound more aggressive and choppy; straight-through designs such as Borla and MagnaFlow sound smoother and deeper. Tip styles include rolled, straight-cut and angle-cut.
From my garage: Call me an elitist, but I will forever be a Borla fan. I have had this on two of my New Edges and would not run anything else. That being said, I do know that the price tag is pretty hefty, so a more affordable setup I would suggest is Flowmaster or Magnaflow.
4. Rear End Gears
Swapping the factory 3.27 gears for 3.73s or 4.10s makes a New Edge GT feel dramatically quicker without adding horsepower. The ratio is how many times the driveshaft turns for each turn of the rear wheels: 3.27 turns with stock gears, 4.10 turns with 4.10s. A numerically higher ratio multiplies torque to the tires, so the car accelerates harder in every gear.
The trade-off is higher highway RPM. 3.73s suit most street cars; 4.10s favor drag strip and around-town driving. After a gear swap, recalibrate the speedometer with a tuner so the speedometer and transmission shift points stay correct.
From my garage: Easily the best bang for your buck on a 2V Mustang, if not every Mustang. When LMR bought my orange car back, the previous owner had installed 3.73s. After driving it with the new gears, I will never skip this mod on any New Edge GT I own. Although it was pretty ragged out when I got it due to being high mileage, it felt very healthy due to these gears.
5. Wheels & Tires
New wheels and tires change the car's look more than any other part and can improve grip and weight. The right setup depends on how you drive:
- Street: 18-inch staggered wheels (wider in the rear) give an aggressive, balanced stance.
- Drag racing: a 15x4 front and 15x10 rear drag setup cuts weight and fits a tall, wide drag radial for traction.
- Road course: lighter, wider wheels and tires keep the car planted through corners.
LMR's own SVE wheel line includes fitments made specifically for 1994-2004 Mustangs. [Author note: name two or three SVE styles and sizes that fit the New Edge, with offset.]
From my garage: I have always ran SVE wheels on my New Edge Mustangs since they are made specifically for the 1999-2004 Mustang. I have had over 10 different wheel setups throughout the years and was never disappointed.
6. Tubular Rear Control Arms
Tubular rear control arms reduce rear axle movement under hard launches, braking and cornering, which improves traction. The factory stamped-steel arms and soft rubber bushings flex under load and contribute to wheel hop. Tubular arms use stronger steel and stiffer urethane or spherical bushings.
The bushings matter as much as the arm. On the lower arms especially, urethane or spherical bushings keep the axle from shifting forward, backward or side to side. Spherical bushings give the most control but transmit more noise and vibration, so urethane is usually the better street choice.
From my garage: Whether you daily drive, track, or drag race your New Edge Mustang, you will always benefit from new tubular rear control arms. I have ran cheaper rear control arms, BMR rear control arms, and UPR rear control arms and while the cheaper rear control arms did the job for awhile on a daily driver, the BMR and UPR control arms were much more reliable and higher quality.
7. Headers & Mid-pipe (X-pipe or H-pipe)
Headers and a mid-pipe are where exhaust mods make real power on the 4.6L V8. They replace the restrictive factory manifolds and crossover pipe.
- Long-tube vs. shorty headers: long-tube headers make noticeably more power. Shorty headers are a smaller improvement but bolt to a stock-style mid-pipe. Long tubes need a matching mid-pipe.
- X-pipe vs. H-pipe: both make similar power. An X-pipe sounds raspier and higher-pitched; an H-pipe sounds deeper, like classic muscle cars.
Long-tube headers and off-road mid-pipes are typically not emissions-legal for street use in many states, and the car will need a tune. Check your local rules first.
From my garage: This debate can be beaten to death, so it usually comes down to personal preference and emissions legality in your city, but I love a long-tube header and high-flow catalytic x-pipe combination.
8. Throttle Body & Upper Plenum
A larger throttle body and upper intake plenum let the 4.6L 2V engine move more air, which supports more power, especially after an intake, headers and gears. On 1999-2004 GT models both parts are common upgrades. The DOHC Cobra engines use a different intake design with little plenum support, but a larger throttle body is an easy swap. These parts pay off most alongside other airflow mods and a tune.
From my garage: When it comes to throttle bodies and plenums, I have always run BBK since they are usually integrated into one in their 73mm and 78mm combinations.
9. Short-throw Shifter
A short-throw shifter doesn't add power, but it makes a manual New Edge far more fun to drive. The factory shifter has long, vague throws. A short-throw unit cuts the distance between gears for faster, more precise shifts and fewer missed shifts at the track. Confirm whether your car has the T-45 (1999-2000) or TR-3650 (2001-2004) before ordering.
From my garage: On my manual cars, I have always ran a Steeda Tri-Ax. I don’t have a ton of experience with others, but it was always affordable and did what I wanted to do without breaking the bank.
10. Front-end Appearance Mods
A few bolt-on exterior parts can give a GT or V6 front end a more aggressive look:
Mach 1-style grille delete: replaces the honeycomb grille and corral with a smooth panel and a chrome or black running pony emblem, and opens more airflow to the radiator.
Mach 1-style chin spoiler: adds a lower lip that recalls the 1969-1970 Mach 1.
2001-2004 style headlights and a short antenna: finish the look for very little money.
From my garage: The first appearance mods I always add to any New Edge Mustang: a Mach 1 chin spoiler and Mach 1 grille delete. These mods were factory on the 03-04 Mach 1s but should have been standard equipment on all 99-04 Mustangs.
Recommended install order for a street GT
For a daily-driven New Edge GT, this order gives a noticeable improvement at every step and avoids paying for labor twice:
- Lowering springs with matched shocks and struts, plus an alignment
- Wheels and tires - Do this at the same time as the drop
- Cold air intake and cat-back exhaust
- Short-throw shifter (manual cars) and appearance parts at any point
- 3.73 or 4.10 rear gears with a speedometer recalibration
- Tubular rear control arms, to put the extra torque to the ground
- Long-tube headers, mid-pipe, throttle body and plenum, followed by a dyno or custom tune
If the car has original high-mileage suspension or exhaust parts, combine those jobs: install gears and control arms together, and headers and mid-pipe together.
New Edge Mustang mods FAQ
What is the best first mod for a New Edge Mustang?
For most owners, lowering springs and wheels are the perfect starter mods to transform the look of your Mustang. If power is the priority, start with a cold air intake and cat-back exhaust, or 3.73 gears for the biggest change in how quickly the car feels.
What years are New Edge Mustangs?
New Edge Mustangs are the 1999-2004 models. They are a restyled version of the 1994-1998 SN95 generation and were replaced by the S197 Mustang for 2005.
How much horsepower does a 1999-2004 Mustang GT have?
The 1999-2004 Mustang GT is rated at 260 hp from its 4.6L 2-valve V8, up from 225 hp in 1998. The 2003-2004 Mach 1 makes 305 hp, and the 2003-2004 supercharged SVT Cobra makes 390 hp.
Do I need a tune after bolt-on mods?
A cold air intake and cat-back usually run without a tune, though some intakes require one. Headers, gears, a larger throttle body or several mods combined should be paired with a tune to get the full gain and keep the speedometer and shift points accurate.
Should I choose 3.73 or 4.10 gears for my New Edge GT?
Choose 3.73s for a street car that sees highway miles; they add strong acceleration with a moderate RPM increase at cruise. Choose 4.10s for drag racing or mostly around-town driving, where quicker acceleration matters more than highway RPM.
Do I need new shocks and struts with lowering springs?
It's not required, but it is strongly recommended. Stock shocks and struts are valved for the factory ride height and wear faster and control the car poorly once it is lowered.
Is an X-pipe or H-pipe better on a 4.6L Mustang?
Power is similar. Pick an X-pipe for a raspier, higher-pitched sound or an H-pipe for a deeper, traditional muscle car tone.
Build a New Edge that's fun to drive
A stock New Edge is a solid starting point, and clean low-mileage examples are gaining value. But for most owners, springs, gears, an intake and exhaust, and eventually long-tube headers turn a soft-feeling 1999-2004 Mustang into a car that sounds, handles and accelerates the way it looks. Questions about fitment for your exact car?
Talk to our New Edge Mustang experts!
