After the first 3k miles on my EV, I started using Mobil1 5/50. I had done 
the very same thing on my 86 Golf GTI which had 220K miles on it before we 
took it off the road. At about 150K miles, I pulled the head...and there was 
little or no ring ridge on the cylinder walls.

IMHO, use the best oil you can, and use a VW filter.

Ric