Not sure what the exact horsepower difference is between the 2 brands. The main difference is the construction of them. The Pacesetters are made of a mild steel, carry a 3 year limited warranty, and have a painted finish. Kooks are made from stainless steel material, and come with a lifetime limited warranty. Kooks headers are a "higher end" header that fit awesome every time and look great, Pacesetters are still a great product and are a great budget minded alternative, they are just made from more economical materials and don't have as much attention to detail as the Kooks do. I have had both products on my personal vehicles in the past and both have performed flawlessly. it just comes down to what your budget allows for and what your ultimate goals are for your truck. If I had it in the budget my first choice would be kooks, if it wasn't in the budget , then I would opt for the ceramic coated pacesetters.