both very unsuccessful. bought OEM from Joe at Zspeed ~ 3 years ago (was by far the cheapest I could find) and I haven't had a leak since.
Also, I'm using oem clamps, and my snap-on screwdriver gets them plenty tight. It's the only snap-on tool I own and I bought it after tightening my clamps using my dads screwdriver. It's the only screwdriver I've found that gets the clamps proper tight with minimal effort.