[Richbot]

a) INCONEL

b) I have the aFe HFC xpipe paired with mine. Shuts up at part throttle and doesn't drone, but is LOUD at WOT. No "cat delete" tune and no CEL, because it uses a 300cell cat. The AA would have to be significantly louder with a 100cell cat I'd think

c) you could hear the MPE on the freeway above 70mph with the stock xpipe, you can hear it a bit more now, but it's not the "boominess" people usually talk about when they're talking about drone. I think the risk when doing any xpipe mods with the MPE is rasp so I like the OP's setup. It's probably 3-4lb lighter than stock too. I can't imagine it being any louder than my car's, and when you're not hooning, mine is just as civilized as say, a stock Mustang GT inside exhaust noise wise.