I would highly recommend editing the "supplier's" name from the first post.
for obvious reasons he's a bit camera/fame shy, at least on bulletin boards.
count me in on one rb25det r33 exhaust wheel.
john - small gains in actual power (5 to 10 kw), but it does enable some shifting of the power curve towards the lower revs. which improves driveability.
also makes a huge difference if you have cams, apparently.
most of the guys last time put them in themselves, but I think you might need to ask someone with a dyno to adjust it for you properly.