I did the conversion in april 2016. Garret T60 turbo running .5bar thru a small intercooler using a chip by Todd at protomotive. I am using VR1 20w50 full synth. It did begin to leak a lot when I first got it running, but I have been able to address the issues and it is now completely leak free....knock on wood.
The car is phenomenal to drive. An absolute blast and it just seems to run better every time I drive it. I find that I rarely use more than a fraction of the gas pedal travel. I can reach positive pressure by 2800rpm and full boost at 3200. It's a beautiful thing!
There have been a few occasions when I did use full throttle (only in 3rd & 4th gear) I noticed some clutch slipping. I am running a mag 915, original to the car ('76), which was fully rebuilt in 2008.
Couldn't be happier with the car!!