@nussmann
Downloaded it & had a look
I see what you mean about it always ending up on it's wheels.
I think it's just in the model, don't think there is much you are going to be able to do about it.
If you set:
<vecCentreOfMassOffset x="0.000000" y="0.050000" z="1.000000" />
in 'handling.meta' it pretty much fixes the always lands on wheels issue, but it introduces a heap of other issues with the weight being so high above the vehicle. Namely, up-side-down pendulum like handling.
Maybe you can work the rest of the handling from there, but it will be a lot of work.
Probably not worth it, without any guarantee of being able to fix it etc