2.25" exhaust pipe is optimal for basic bolt-ons.
If you are truely planning on getting a header,
go with 2.5".
Things to ditch;
The flat, black silencer that sticks out towards the front of the car.
The black accordian tubing.
All the stuff in the fender.
And the triangulaur rubber piece that connects the airbox to the fender (replace it with a piece of 3" pipe).
Keep the airbox and the plenum above the TB.
The plenum is their for an air reserve.
It benefits throttle response and helps to keep idle smooth.
