Getting the exhaust gasses out of the turbo is just as important as feeding them in. When you need ultimate spool, you need a 3″ exhaust system. Mufflers, cats, and sharp bends all restrict the exhaust and create pressure after the turbo, making it harder for exhaust to leave the turbine, handicapping your spoolup.
The way I have my system set up, I the exhaust will be routed through the muffler to keep the sound down for cruising, but with the flip of a switch will let loose through the straight pipe for “kill mode.” 🙂
Helpful Links
More information on my exhaust system
Doug’s Headers Electronic Cutout (The highest quality of all the units I researched)