find a way to increase your drives

it will be slow as a dog but will yeild the best results. not sure how you can do this on a automatic, but you could always increase your tire size

use a SRI with a k&n cone filter for the intake

on the exhaust:

it's not that you need the backpressure, but exhaust goes in waves (it's alot like clapping into a pipe or something, every time your car does a revolution it has 4 exhaust compression waves) if your piping is too large it wont fill the entire pipe and then it will spread out, and actually some of it will try and get back towards the engine fighting itself on the way out. with an exhaust thats too small the engine have to work to try and get the exhaust out the pipe. stick with stock sized piping. and if you want to go bigger go with a GSR exhaust from a 00-01 GSR i'm pretty sure it should bolt up.