MT-90 is too heavy. I know people are using it on track. Even BimmerWorld that recommends RL for everything, doesn’t recommend MT-90, even for track for my model. MT-LV heaviest they recommend.I had a problem with the MT-90 in 2 different car transmissions calling for a 75W-90 and were "recommended" by redline's website. A 1995 Pathfinder and a 2004 Audi A4 1.8t. Both shifted like **** in anything under 30 degrees F until the trans warmed up. 20 and below was like shifting through mud. Once I went back to OEM Audi fluid shifting was never an issue again. The pathfinder I ended up trashing cause the frame was rotting out. That's not to say that it is a bad product or any of their products are bad. Just my experience with MT-90 in 2 different vehicles. I haven't used their engine oils yet. I have Amsoil gear lubes, oil and ATF in my Stage 2+ 2.7t S4. I haven't had any issues. Though, my sump is ~8qts now since I use the bigger oil filter and an second oil cooler.
D4 works like a champ. No issues shifting after vehicle being parked for 8hrs at -34 few weeks back.