Yes i run a mugen twin loop, and yes it's worth switching. It uses 2.5 inch piping, not to mention a 2.5 inch collector between pipes, it's fitment is perfect and the welds are amazing. The Mugen exhaust is not only nice and quite, but even without i cat, as I took mine off, it's not at all what so ever raspy, it realyl sounds great. It also gives a nice deep tone where the stock is a little winey in comparison especially without a cat.

Any way, good luck,
Aj