Twinloop muffler

Offset for a muffler is like where the placement of the inlet is. So for our car types, the inlet offset should be on the right as our exhaust piping is on the right hand side etc
Reason I bought the S12 was for its sound/flow, shouldn't be too drony
Sound clips

Mugen
http://members.cox.net/teamintegra2/mugen.mp3

Replica
http://members.cox.net/teamintegra2/hytech.wav

Or if you want best of both worlds with adjust-ability, the varex. You really can't go wrong with either lol.
Check out RaceNation, thats where I got it for cheap.