The PWC m235's, which i have sat in, been up close etc have to be detuned in order to meet the requirements for the TC class.
I cant speak to the Cup series.
I also have no idea why ppl are defending a stock piece of plastic. I ripped all the plastic out and replaced with the ER andonized pipes first week i had the car because its been a known issue since the n54's.
If you think your stock will do the job, good on ya. Everyone here is trying to help you avoid a problem.
<- my car running pretty hard. Popped charge pipe at same track in August the year before.