Supercharger Bypass Valves....

I'll be running a 16# pulley - looking for a good bypass valve for an ATI ProCharger P-1SC (which will be upgraded to a D1 this winter) - I was thinking about going with a Vortech Mondo bypass, but it's about $260. I think ATI makes one, but I've never seen or heard anything about it. Anyone?
 
I was going to suggest the ATI race bypass too. I plan on having one installed on my car in the very near future since I have been pushing quite a bit of boost with just the stock bypass and it is the most annoying fluttering I have ever heard.