After an oil change I warmed it up and watched as a very small amount of oil leaked out from between upper right side of the oil filter cover and engine.  But only under >4000rpm load. O-rings, acorn nuts, and studs are all new. Torqued to 8nm. HOWEVER, one of the studs backed out as I spun the acorn nut, same side as the leak. Thinking the dimple between the two threads of the stud had been flattened, I replaced the stud and buttoned it back up, still leaking slightly. I think there are two possible causes here:

1. The stud is not secure, so the o-ring isn't completely sealed. BUT if this is true why would the torque wrench click at 8nm?
2. I'm not torquing high enough. BUT I'm ascared of snapping the cheesy stud which is a nightmare in itself.

Fire at will

Are you sure the case and/or cover aren't cracked?

Could just be a little dirt between the cover & engine case, or maybe a faulty oring on the cover.