What's everyone's thoughts on this...

Assume 90+ degree heat and VIR? I'm thinking of running some 15-50 weight oil for a 2 day event.

Stop by a BMW dealer and pick up some Castrol 10w60 full synthetic racing motor oil its what the M3's came with. Not only is it thicker BUT it has a higher zinc content which is what stops engine wear.

Here try this link, it has more links you may find useful. Explains about Castrol TWS.
http://www.m3forum.net/m3forum/showthread.php?t=295656

Cool, thanks for the info. Trying to avoid the dreaded "Engine oil hot" light.

It was hotter than hades there last year.

Heh... just read the first 3 posts... man, I hate oil usage threads! ;)

Sorry.. I don't want this one to degenerate into he said, she said. Was just wondering it it's a good idea to go to a heavier weight oil.

The simple answer is YES. A thicker oil will help protect the engine on hotter days when driven hard. Thats why I mentioned the TWS as thats exactly what BMW and Castrol designed it for, sustained high speed high performance driving in race conditions.