[Dominik]

I used 3/8" individual flanges (in fact 10 mm) without gasket. Studs with the serrated face nuts (ARP). I feel the the less restrictive your exhaust is, the less it leaks at the headers.

When I had more time, and no friends(!), I safety wired the header bolts. Thank you ARP for those nuts! Now I can party more.

On a side note I always use slip-in headers to sidepipes to keep the vibraions away from the pipes which often lead to cracks. Okay, I know, that wasn't part of the question...