Originally posted by papadage:
By the way, I expected some gains from the headers without a new catback, but I was very pleasantly surprised by the sound comin gout of the stock exhaust and by the seat of the pants impression. Feels very nice on the low end, almost no drone, and great general passing power.



If you are still running a stock SVT catback then you really need to open that biotch up!

I wouldn't mess with anything beyond the y-split back, but I'd run 2.5" cat and piping straight back to the y-split. Inspect the y-split for good flow, replace it if it looks [censored]. The other pipes will be fine for your 2.5".
The resonator should be deleted or replaced with a better design.

This would be a good $400 project and net you some more ponies up top.
Do a baseline dyno run.
Then I'd recommend pulling the heads, P&P with bigger 30mm exhaust valves.
THEN do another dyno run.
THEN get the chip and tune.
Then get nitrous!!!

Former owner of '99 CSVT - Silver #222/2760 356/334 wHP/TQ at 10psi on pump gas! See My Mods '05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red '06 Mazda5 Touring, 5spd,MTX, Black