I’m about to install fast intentions hfc on my coupe that has a muffler delete, and was wondering if anyone here know how loud it’s gonna be, it’s already decently loud with the delete. I will say I didn’t do the muffler delete and wouldn’t have been my first choice, but it was like that when I got it, also part of the reason I’m getting hfc is because my oem cats are broken

 

It's gonna be loud AF - put some kind of muffler on it like this and it will have a nice deep growl. Going through this myself right now because I caught a pothole and cracked my Borla muffler and it's unbearably loud to drive.

 

Kova-Motive on YouTube has a decent review of HFCs and a muffler delete on his G37. That's a 6mt sedan but it should be relatively similar. I had HFCs and Manzo axle back on my coupe and found the drone pretty annoying.
I think HFCs is the right move based on your OEM ones needing to be replaced but I'd plan on an aftermarket axle back or catback in the future. I went with Fast Intentions CBE and stock cats and loved it.

 

Which FI HFC are you going to get? Last I heard, the one on Z1 does not fit the G37X Coupe. I would also like to get an FI HFC, so I'm intrigued!