hi there! as the others said no rear or centre muffler is best, just pure straight pipe etc... however if ur gonna opt for no muffler probably better u dun jus leave it as a downpipe, at least weld some more piping till the back bumper or bend it till it sticks out 2 the side (under left/rite door), guarantee will still b noisy no worries!! if jus downpipe rite what if fire come out during rev-hard session??
or if u must have muffler, u get those super noisy ones from wei yip and u make holes in the exhaust piping also damn kao f.cking noisy - guarantee wei! hehehe but per4mance may drop a bit la hehe!