I feel like it isn't the smartest idea to run stock dp back. I'd think about running stock cat back but I'd run test pipes.

No reason for those things on there other than to restrict air flow.

 

the stock catback isnt very restrictive at all.. smaller diameter but flows fairly well

i ran stock catback with a 3" cutout, the differences were about 15-20whp on the stock turbo iirc.. i think i have the dll graphs somewhere

 

James is running the stock exhaust from the cat back (Buschur DP, stock cat, stock catback). He had a QTP electronic cutout on his DP as well. James has since switched back to a full 3" exhaust, but when he would get on it with the stock exhaust and the cutout closed, the car sounded like it wanted to shoot out the cat. This is the same setup that I'm running on my HTA3794 setup.

 

Bump,,, I want to know also,,,
I hav a FPRED.. and want to put the stock catback on,, But run it with my 3" testpipe and after market DP.. Just to keep things quiet and stock lookin..