says "it's not a bad idea to use thicker oil (15-50)...due to the extreme heat turbo cars make".
Experts in all fields can and do disagree. Mike Smith of JWT, for example, recommends 10-40 - even for cars that go to the track. A Nissan mechanic (specialty shop) suggested I run 5-30 this past weekend at the track, and my local shop owner suggests 20-50. One must remember, of course, that all petro-based oil weights are not the same as synthetic oil weights.