Exhaust on a GSR swap is pretty much a custom job, as the different lengths neither a Civics or a GSRs is correct. Of course if you buy a ITR header, you'll be fine with a Si exhaust and cat set up, as the ITRs is the right length.
Turbos and other motor parts, you buy for the motor whether or not things like AC or PS is kept depends on the kit, not the car, as the bay are almost identical. Most cold airs for XXXX motor are the same too, with AEMs hybrid series being made to insure all the bolts correctly line up, but mopst can be made to fit with little deviation.
Suspension and chassis products are bought for the chassis, ie EG/EH suspension, by for a EG/EH.