I have driven about 500mi since installing my SSI HE's. I now have an exhaust leak.

When I installed these I carefully flattened the stub pipes and annealed the copper sealing rings.

I used neverseize on the studs and used shouldered copper coated nuts.

Question, should I just find the leak and tighten the nuts further?

Also the set-up with the shouldered nuts bearing on the mounting ears of the HE's would seem to create a lot of friction and affect torque values. does anyone install a flat washer under the nut?

I installed the sealing rings "dry" what about a light coating of neverseize or of hi-temp. RTV.

Looking for opinions and empirical knowledge, thanks!

Check to see the exchanger mounting loops aren't bottoming out on the head's stud shelf. I had to file mine to provide clearance for correct gasket seating. Also, check for leaks using McMark's technique of pressurizing the exhaust using a shop-vac and searching with a feather. This works very well and no heat to deal with. I wouldn't just add more torque to the studs, that's asking for trouble.
Good luck.

don't just increase the torque value. one key is to bring them up in stages working in an X type pattern. just barely snug (enough to keep the copper gaskets in place), 5 more lbs, repeat, repeat. fully torquing one and proceeding can 'cock' the he's and you could break a stud trying to seal them up.

That Mc Mark is one clever dude

All good, but also the nuts can loosen. Mine certainly did. They are most likely to do so right after installation. Tightening back the offending nut can help quite a lot. Aim being to seal, not pull out the stud of course.