In prep for a turbo I went ahead and had a full 3" APEXi WS2 catback put on my S2. I Havent noticed any real diffrence in power. Everything I have read has said that any kind of exhaust either drops hp or keeps it about the same. I figured a single 3" would dramaticly reduce hp but i consulted the butt dyno and it doesnt really feel any slower. when racing i still pull about the same on the people i always race, and times at the track are only a little slower. Any idea on the amount of loss to be expected from this type of exhaust setup.