"I dont even bother with orings any more, i use hi temp RTV and put a nice bead inside the pipe where the oring sits and another on the exhaust flanges near the ends of them. let both dry and put the pipes on."
BTW I didnt realize that was your screen name over there
i use the oring's , i coat them real good with a coper based high temp silicone and slip them on the flange. then i put silicone on the flange and in the pipe flange ,then i let dry to a tack .then i put the pipe and springs on and let fully dry for about 48 hrs . never Had any problems leaking even with a turbo, and it creates allot of back pressure in the pipe. just like ( bansh- eman ) stated silicone is the way to go