Quoting beaner:
The first version of the Snaypse bov had many issues. The revision is the version you're after if you want to run it.
I picked up a revised version used and it came with what looks like a standard flange that can be welded directly to the IC pipe. The way it adapts to the bov, there's no way I see it sealing. I bought a Tial adapter and flange. That setup looks FAR better.
All said and done I decided to just mod the stock bov instead of try it out. /ubbthreads/images/graemlins/crazy.gif
Many versions of the synapse bov's have problems regardless of flange type etc. Personally mine used a tial flange, as did my friends which both leaked quite a bit from the flange. The tial BOV's however seal up fine, so either they didn't machine their adapter flange correctly, or their oring was crap. I bought another new o-ring from them to test it out and the bov still won't seal up.
I know this is a wastegate question, but the reason I bring up their BOV's is because the company uses US the consumers to "test" it's product, that and I've had less than stellar support from them. Go with a tial or turbosmart!