This may be a weird question.... When running the drain for a turbo into the oil pan it must be at a slight slope to prevent oil pooling... What happens if you are going down a hill? Would the oil still drain? or would it pool in the line? Just one of those things I got to thinking about.....

 

I have a t70 frt mnt on a 98 TA and mine would smoke during heavy braking. To solve the problem i added a inline oil pump between the turbo and the oil pan. Totally fixed the problem!!! I dont remember the part number but i think i researched Porsche oil pumps. I'll try to do some research and come back latter.