Originally Posted By: A_Harman
Yes, the viscosity and HTHS will work out so that it is still a 20-weight oil, but since their race oils have low TBN, it probably would be a good idea to cut the OCI by 20%. TBN of 6.7 seems pretty low to go 10k miles.
I agree. I'm a Red Line fan too, but I don't see much ROI in average vehicles, especially since you can't extend the OCIs.
In your Focus, I don't imagine it'll be any benefit at all. You could probably use a $20 jug of QSUD and achieve the same results for one-third the cost. I like RL in my bike, but it's air-cooled and can get hot. Even in that, I'd be using M1 15w-50 if I hadn't picked up the RL so cheap.
Still, it's your money. Use it as you see fit.