Redline Fluids - A quick empirical report
A few months back I decided to deviate from the BMW recommended TWS motor oil and OEM transmission fluid. My car is an 08 with 40k miles on the clock and tracked 5-6 times a summer. I change my oil at double the recommended interval, and I believe my trans fluid change was the first since the 1200 mile change.
Using TWS, I would burn a litre of oil every 3 track days. After 3 track days using my Redline blend (8 quarts 10W60 with one quart of 5W40), the car hasn't registered any oil loss. I blended the two grades in an attempt to match the 100C kinematic viscosity of TWS, as the redline is a bit thicker. I'll do a blackstone analysis of the redline when I drain it. FWIW, I have noticed absolutely no change in mileage after switching oil (a good sign IMO).
As far as the transmission is concerned, I went to Redline D4 fluid. Initially, i noticed no difference in shifting compared to the fluid I pulled out. A couple track days and a thousand miles and the transmission now shifts a bit smoother.
For anybody considering Redline, I've noticed no noticeable drawbacks of using the fluids.