How would a USDM factory ITR cat back flow for a mildly modified LS?
(mildly meaning, i/h/e, fpr). Thanks.

 

will flow great. i recommend removing the bottleneck tho

 

and it won't sound like -waaaaa waaaaaa waaaa

 

Thanks guys. At what point, in terms of horsepower figures would you recommend that I move on to an aftermarket exhaust system (one that flows better than the factory ITR)? I've heard that the ITR exhaust begins to compromise high end performance when horsepower figures are ~ around 200 @ the flywheel.