Well, car is on the trailer and going to the shop for a new exhaust at 8AM Saturday morning. My exhaust guy does custom work and has a madrel bender. My T3 turbo has a 2.5" turbine outlet.

CURRENT SETUP:
2.5" from T3 turbo to stock cat. Also 2.5" from stock cat to Arospeed Bomb muffler. The muffler has a 2.25" inlet so there's a reducer on it. The exhaust is LOUD and rattles on startup and buzzes some.

NEW SETUP:
2.5" from T3 turbo to high-flow cat with flanges. I'll have a test pipe with flanges made so I can interchange testpipe/cat setups. Then 2.5" to a CherryBomb glasspack resonator with 2.5"in/2.5"out. Then 2.5" to a Magnaflow muffler with 2.5" inlet.

What do you guys think? I'm also considering 2.5" out of the turbo then immediately enlarging to 3" and using 3" throughout with a 3" cat, muffler, and resonator. I have a custom stage 3 setup running 15-23psi, highly modded ATX with a 3500 stall speed.

nice setup doug.

if you got it set up for 3" i would go that way.

im going with a 2.5 all the way through. and test pipe all the way!

______________________________
Matt D.
'06 Evo IX SE
'98 RS-T 13.8 @ 106.1

That is kinda the same route that I'm going to take. My dp is 2.75 then down to a stock GST cat back.
My new setup will be dp to 3" no resonator/cat, to my tenzo venturi.
I think you are going the right route.

Kevin
The old:


The new:

Well shit... my custom exhaust guy has quit the shop and the other guys don't feel comfortable doing it. Another shop I found can't do bends with less than a 5" radius.

So it looks like I'll be ordering a tight-radius (3") mandrel bend from JC Whitney and do it myself.

I'm going with 2.5" piping throughout with a Magneflow 40-series DeltaFlow muffler, dual chrome tips, Thrush glasspack resonator, and a flanged catco/testpipe interchangable setup. This should perform and sound much better than my current setup.

keep us posted on how it goes. I wanna see cause I have to redo my entire exhaust.

i have a very similar setup. i took the HRC downpipe and had a 2.5" press bent "turbo-back" exhaust made up. i had the cat flanged and a test pipe fabricated - right now i have the test pipe in. it sounds really nice with the magnaflow muffler. a little ricey at low RPM's when everything is cold, but other than that it sounds quite nice. spoolup is good too. pulls better up high than it used to.

2016 WRX STi Limited (current)
2001 A4 1.8tqms (donated)
1991 GVR4 #1933 (sold)
old.dsmregistry.com/detail.php?carid=218 (dismantled)