What muffler do others use on LRP to quiet thier cars down a little?

Right now the 2.5L I6 (m50) has kraftswerk headers, and 3" straight back to a borla muffler.

This is a world challenge spec setup and I believe was as is at lrp this season, however I am not sure if it was muffled extra for the event.

Any suggestions would be great. TIA