I just installed Ark grip exhaust system on my 2012 G37X looking at adding a high-flow cat to the mix what the fits the X sedan. Looking for performance gains, not really the sound.

 

Fast Intentions resonated high flow cats! You will love them great quality worth the wait

 

Any reputable HFC brand should serve you well. If you want resonated, Motordyne and Fast Intentions are your only choice. For non-resonated, you have Berk, AAM (currently have these and love them), Fast Intentions, Stillen, Z1 Motorsports, and Invidia.

 

You should post a budget as it can make a huge difference in your options. Now, if I had 800$ to get HFC or some sort of upgraded cats, I would get ART pipes, especially for performance and sound. Now those aren't HFCs , but i feel berk HFCs are on par with the loudness but not the sound quality. If you had 350$, look into Z1. That's what I'm running with my Ark and it's been fine. If you have 500$ and can wait, FI RHFC is probably the most popular choice among this forum.

 

Actually, it's $685. Although if 1cleang is still holding downpayments for group buys, you can probably get them for $650.

http://www.fastintentions.com/produc...roducts_id/159

 

AAM HFC for $425 shipped from Kyle @ ImportPartsPro

 

I'm looking for a HFC, interested in performance gains, without getting a CEL. What is the best option

 

I loved the way my ARK sounded with oem cats, hated it w/the HFCs...