the rear rotor runs hotter than the front.

what are your oil temps like?

 

Check Your Intake Manifold To See If It Is Warped.

 

Another easy check you can do if you still have the damaged plugs is to check the thickness of the crush washer. When properly tightened it should have a thickness of 1.45mm or less.

If it is thicker than this, the plug was not tightened sufficiently and could have caused the damage. If it is within spec then your issue is most definitley happening from abnormal combustion or overheating.

 

possible solution

I think you may have your connectors crossed, i had the same issue. My engine would eat tailing plugs quick, leading is like new.

I had accidently crosed the connection from the coils to the ignitors -tailing coil to the leading ignitor/leading coill to tailing ignitor so it was actually running my leading spark through my tailing plugs with the msd.
all that i needed to do was switch the connectors on the ignitors, and set timing properly, all is good again, and I learnt to not rush wiring even when it looks straight forward.