So 1500 or 2200Kv motor would be good, and I can offcourse make different gearings etc. if there are problems with speed or temps.

What would be you choise ? 40-55Mph sounds good speed if we think about the good handling and driving.

So Neu 1515 1.5Y or 1Y would be good, which would be good choise to my setup ?

I think the 1Y is overkill with 6S batteries :P