what oil to use

No, the EPA told GM they have to change it.

Theres a new EOS coming out, should be in the dealerships soon. The old EOS sells for like $15-$20 a can on E-bay.

Best now is to use what Comps or Crane sells, that is market towards race cars, not street motors.

Speaking of racers, this is one type of break in oil they like to use.
http://shop.joegibbsracingoil.com/Content/product-28-1-19.htm?VPID=29&TPID=30