First time I started my car with the turbo bolted on was 3" open DP...in a small, one-car garage. DAMN. Loud. Tried driving to Ben's with the wastegate wired open, but got pulled over and sent home right as I pulled onto the main street.

I would never wish that upon anyone.

 

http://www.quicktimeperformance.com/



That'll do donky.

 

My old turbo setup was more quiet with open downpipe than my roommates 91 with a old cat and a straight through resonator.

 

I've used a 3.5" DMH cutout and spoolup was improved compared to the 2.5" muffler (small impact on boost threshold, yet notable difference in transient response), but I would recommend giving the cutout priority flow. The QTP merger is a piece of ****.

 

Maybe I'll unbolt the exhaust and fab a turn-down tip onto a flange to put on the end of the downpipe for race days... More work than I want though... Kinda rather do the cut-out switch.
Seriously, I need to find a guy in CA who can do a custom DP...

 

If you buy into the enthuza exhaust GB. Call him up and talk to him. I bet if you tell him you want a test pipe for you car, with a built in manual cutout, that he could do it easily for you. He would have to cut two angles and weld one extra flange on the end of the cutout but you could get him to tack weld studs in that flange so you use wing nuts to hold the plate on when not in use.