Borla seems to be the way to go when keeping the stock NPP exhaust. Sounds great

I wanted to chime in with a quick comparison of the two X pipes since I just finished installing both back-to-back. We installed the Corsa X pipe on my ZO6 and the Borla catless X pipe on my Dad’s GS. Both parts and hardware were of equal quality and install was straightforward with two people and the use of lift. I think the Corsa was a little easier to install and I liked the hardware better. Both fit very well and we checked for leaks and there were none. Now for the sound, I don’t have anything new that hasn’t been said already. The Corsa is louder than the Borla on high-rpm revs and it has a higher pitch. I love the tone and I think it will sound nasty at WOT on track. The Borla amplifies the stock tone and sounds great down low. It’s throaty and growls. On cold start, not much difference between Corsa and stock. The Borla sounds deeper and it’s more of a noticeable change compared to stock than the Corsa is. Since it’s snowing here we didn’t get to run the cars to really hear the changes compared to stock but some healthy revs were very enjoyable to listen to. I personally think both sound awesome and it simply boils down to which you think sounds better. That being said you can’t really make a mistake either way. And another plug for Josh at Meraki Autoworks as I bought both X pipes from him and it was a great transaction.