Sorry, I did try searching on this topic and came back with dispersed and unsatisfying results. Right now, I have an 04 GT and want more sound than my weld-in 40 Delta series are giving me. I do not, however, want to remove the midpipe.
I have a question on which way to go or if there is something better than what I have here:
1. Hollow out the stock cats, leaving o2's in place and functioning (will this throw codes?) and keeping the Flows.
2. Keep the cats as they are and going muffler-less.
3. Keep the cats as they are and getting Flow's 10 series (one-chamber).
Drone is not a concern. I fancy the sound, actually.
Thanks for any advice.
I have a question on which way to go or if there is something better than what I have here:
1. Hollow out the stock cats, leaving o2's in place and functioning (will this throw codes?) and keeping the Flows.
2. Keep the cats as they are and going muffler-less.
3. Keep the cats as they are and getting Flow's 10 series (one-chamber).
Drone is not a concern. I fancy the sound, actually.
Thanks for any advice.

. I think the 1 chamber flows are the race mufflers? I think they have the most drone but like you said, that's not an issue. That would give you a louder sound. You can always buy a catback and keep the factory midpipe. Magnaflow or the SLP straight throguh designs will give you plenty of volume while keeping the stock H pipe.

regarding the nullification of warranty. I was fearing OR H because of the dealer negating the effects of the warranty. Anyone got any sites where there is a cheap H without cats?