I am debating on what axleback exhaust sound the best for 2013 Boss 302s. Borlas I know have that deep sound that I like. And been watching some videos on Mrt Axleback that sound good to. Will be running Mrt Offroad H Pipe here soon.
To each their own, but I could never deal with the sound of removing the cats. If I did though I would not use an H-pipe, I would go X-pipe. I don't think it's going to matter a whole lot on what straight flow muffler you use, it's just going to be loud as hell. I can't see you going chambered since you are removing the cats, seeking cfm. Give em hell though!
I put on the RTR system by Magnaflow. Love the fact that is it pretty unobtrusive around town but lets you know its there when you give it the beans..... 2013 RTR Exhaust 2013 Boss 302 - YouTube
I have stock exhaust untill the GT500 axle backs, and my friend with an 11 GT500 says my car is the best sounding car he's ever heard at WOT. I love it to, but would love to hear what it sounds like without cats.