I know the consensus is larger = better, but what if you're running a small turbo, like a T25 or T28... will a 3" still be best, or is a 2.5" okay? I am interested in getting in on the group deal for the stromung exhaust if it gets cheap enough, it was recommended to me that 3" isn't necessary unless i'm going to be pushing out 300hp or more..... i want a compromise between performance, not too loud, etc.... i guess i cant have it all...

The larger the exhuast the better. Backpressure is turbos enemy
If you plan on running over 12psi on the t-25 alot i recommend the 3inch , just for precaution. You will be fine with 2.5 though.
Just that with the higher boost levels on the t-25 a 3inch would be nice.

Larry

are there any advantages to using the 2.5" vs 3" like faster spooling, less lag, better response, etc. or does 3" basically spank the 2.5" at everything

What i noticed SOTP was that the 2.5 had a little better low end torque where as the 3inc had better top end . The 3inch seemed to spool faster as well but the torque was moved higher in the rpm range. So basically the 2.5 inch would be more violent tire action where as the 3inch wont be as "violent". I did tend to get better rolling burnouts in higher rpma range in 2nd and low rpm range of 3rd. I did not have a cat either straight from turbo back.
Lots of damagin wheel spin to my front suspension, tore my bearings and bushings up. Hopefully now after replacing the bushings, bearings and correction of alignment . I might be able to muster up a better 60ft.


Larry

I thought Stromung exhausts were only 2.25"...