hey i have a peakboost turbo kit, with a 3" 76mm downpipe, if i use a t1r-70mm 2.75 exhaust, will i lose much airflow and power, the car will push a little over 300whp i just love that exhaust, but if its gonna be a problem ill have to use 76mm what do you guys think??

 

That that piping level, not that much, but it will create some backpressure. If you have it, use it, but understand the limitation of the exhaust. 300whp can be done depending upon the engine platform.