Car - ae71 pano

motor - 4ac

use - not daily

problem -

occurs/started when - i did a key banger lol

personal situation -
so of the three cars i got registered 2 have blown up exhaust systems and one has a BHG so its time i started fixing them up.

anyway my question is what should i do for an exhaust system for the 4ac considering I'm planning for a 4age soon?
-should i just get something made from the flange back?
-what size pipe/mufflers to use?