None raced car, throw the stock cats on it and have fun. It will also cut down the noise too.

 

Theres definitely a difference between TP's and stock cats with or without a tune. If you are looking for the power TP's are most definitely worth it.

I've switched from TP's to stock cats several times. While I like the power of TP's I prefer the sound of stock cats. (TP's with stock exhaust sounds really bad).