I'm going to re-torque my new wheels should I get the wheel off the ground first? or is it ok to leave the car on the ground?

The weight of the vehicle does affect a few of the bolts slightly when on the ground, I recommend lifting it just off the ground, then, lower it where it just touches the ground, to prevent the wheel from moving while you retorque

Sounds good to me,I'll do it that way.thanks