I'm currently using RLI HD SHP 5W40. It's a heavy duty biobased lubricant that was formulated by Terry Dyson specifically for high heat, turbo, DI, etc. applications found in the Audi RS6 and of course the N54. So far what I've noticed when compared to BMW 5w30 is that the oil runs about ~20 degrees cooler (oil sits at around 220 degrees after reaching normal operating temp compared to 240-245 degrees) and it cools down MUCH more quickly as well; I have a feeling this would be very beneficial for those who do HPDE's and other tracking events in order to avoid and/or prolong limp mode.

I'll run it for ~7,500 miles and then send it off to Blackstone for a UOA. I'm fairly easy on this car, so if I can get 8k+ OCIs out of this oil that would be great! Other than that the motor runs smooth/quiet with no other differences to note. Only time will tell how it stacks up to more conventional lubricants but I'm excited to see the lab results.

Here's a Tech Data Sheet on the oil itself for those who are interested:
http://www.renewablelube.com/synxtra...otor%20Oil.pdf