It's not necessary to drill a hole in the throttle plate with this throttle body. That was a tuning trick that was handy on stock throttle bodies where there wasn't a lot of adjustment allowed from the throttle position sensor. Drilling a hole allowed you to let a bit more air in without messing up the TPS setting. Drilling a hole is an option, but you can also adjust the throttle blade, then use the adjustable throttle position sensor to reset your TPS voltage to compensate for the new throttle position. Many times, idle quality suffers when the throttle blade is too far shut, causing the car to rely on the idle air control motor to make all of the adjustments. The idle air control motor is designed to make finite adjustments to idle only. If it works too hard because the throttle blade is too far shut, it often leads to surging and dying issues. By opening the throttle blade a little more, the IAC doesn't have to work so hard. Set your idle to 8-900 rpm with the throttle blade adjustment screw, and the IAC unplugged. Once you plug the IAC back in, it will adjust to the new idle rpm after a few minutes of driving. If you're running a big cam, a higher idle speed may be necessary.