It's actually an easy one to do yourself. I used Mobil 1 and changed
it every 10k, with a filter-only change every 5k. It ran better at
150k when it was totaled than new. You probably want to stay with
something with a -40 or -50 to keep the charger happy. I don't know
if it really hurts anything, but the supercharger seemed noisier
with lighter oils.