I have two BMW racecars e36 M3 and e46 330i. The easy button is Redline 40wt racing oil and it is what I have always used. I am tempted to switch because FCP EURO sells MOtul 300v 5w40 and will allow you to return used oil and will send you new oil so I could lower my operating expenses for the frequent fluid changes by 1k+ at a minimum.

Here are the data sheets
Motul
https://d23zpyj32c5wn3.cloudfront.n...0Power_205W-40_20_28GB_29.pdf?1492017370

Redline
https://www.redlineoil.com/Content/files/tech/40WT_RACE_PROD_INFO.pdf