Using a very compact 40mm gate with a 14psi spring, with a vac line running back for boost source. Can't see it from behind the car. Opens at 14psi obviously, providing a bit more flow. I don't have any data yet to quantify the effectiveness of this mod, however i plan on doing some of that down the road. No pun intended. Ha. I like the 14psi spring because you can still get plenty of quiet acceleration, but then when you are smashing on it, sounds nasty as it should :)
For those wondering why not just get a system that is 3" from end to end? #1 this exhaust is very very quiet, #2 i wanted something, uh, different i guess? I had a 3" TBE with a magnaflow on my GVR4 for years...time for a new sound. #3 This was a good outlet for me to have some nerdy fun. I enjoy this mod!