I'm running a Tial BOV - I was running a single HKS SSBOV, and was getting some "back surge" - I was going to just add a second, but just one Tial is plenty. Excellent construction. very cool sound - supposed to be very solid, leak-proof, etc. (I heard someone say "race grade").
I actually still have my HKS on a lower pipe! Didn't have a chance to get a new pipe fabbed to remove it - hahahah, you should hear my car at WOT, with the back-to-back HKS->Tial blow off sounds. I'm sure I'll eventually pull the HKS, so I may have one for sale in the very near future.
I'll take a photo if you're interested in how it looks - if you're not overly concerned with cost, it's supposed to be the best there is!
I called HKS and they said the one I have isn't technically a BOV but actually a release valve or something. He claimed that for the single application I should be using their Racing BOV Type II. I will still have to weld a new flange on for it so I just might use the TIAL. Can you email me ([email protected]) the pictures when you get time? I'm running off to the dyno right now. Thanks in advance!