Check your coolant for any traces of oil to determine if it is the head gaskets.
For piston rings, run your finger around the inside of your tailpipes and see what you get. Some black gritty grime is normal but check for oily residue. Clean them out for a good clear test.
You can also check your PCV system, with the higher compression you could be sucking oil out of the crankcase through the PCV valve. I favor replacing the whole PCV deal with crankcase filters. My mildly modded gt had very oily PCV tubing (whether normal or not, this cant be good).
Also watch for oil gnomes and lube fairies. Those bastards have wiped my oil pan clean numerous times.