Upgrading exhaust question(s)
 

Hey everyone, first post I think, or 1st in forever! Over a year ago I bought a 2005 Maxima SE which the previous owner had upgraded w aftermarket exhaust system & headers ( & several other things as well)..a lot of the mods were badly done- the exhaust was probably a home job or something... One pipe was hanging an inch from the ground shortly after purchase (car is lowered), multiple hangers have slipped out(maybe broken off?) Since.. It looks to be hanging on by only a few bolts probably. Idk what could cause this but the pipes have seemed to push backward, so that they stick kinda far out from the back. This has happened over time. I think it just needs to be redone. But I know very little about this - what is the best I can replace it with? What should I be looking for? I want good sound, but not necessarily super loud though. Idc about higher end gains cuz I'm not racing, I'd rather have better lower end/pickup if anything!
also my mechanic friend said the headers are "bent" - i'm assuming that's a bad thing? Do I need any different parts or different installation having headers or no difference? Sorry for all the questions, I'm still very much learning! Haha. Thanks!