Another plastic VR6 rocker cover question

[bananawhip 0]

I know the late ones are more sound deadening and the early ones look cooler but which one runs the hotter oil temps?

 

I have a metal one fitted which I caked in paint to stop heat transfer to the inlet manifold and now my engine runs 8deg hotter :shock:

 

I could sand it all off again but if the plastic one offers even lower temps as standard then I might just slap one of those on to save the trouble...

 

Any ideas would be very much welcomed :)