Thanks to all for your very warm welcome!

It's a pleasure to share pics with you and I'm going to write some details along with the pics.
I'm also interested in data logging and will try to find out what's suitable for this car. Am I right that eagletree is limited to 150 amps? That might be not enough.
The calculated speed should be 60+ mph with the original gear-ratio (16/48) but I took a shorter ratio (14/48) to get more torque as it is still fast enough.
The highest temperatures i got were 140°F at the ESC and 120°F at the engine.

First 4 pics show the belt drive-unit for the 4WD.