Hello again,
thought i'd share the last news here. I've had the conversion ready and street legal since last fall. Have been testing it some 6-7000 km's after that. Freeway, city and circuit.
The car is very fast with the current ratio of 3,69:1 (open diff) as final drive and 1:1 in 5th with ZF dogleg 717.450 gearbox.
It's also very reliable. No issues what so ever.