Something that really is make or break for 4wd cars is proper throttle feel. It is hands down the most important part that is not properly addressed. A light 4wd near 50/50 weight distribution with all 4 wheels hooked up directly to an electric motor is dramatically influenced by the way the motor, throttle curve, drag brake, and push brake feel.

Almost every 4wd somebody hands me and says "here, you tell me what's wrong" is under geared or has unhelpful drag brake. This makes the car very touchy and hard to drive. Drag brake, which can be used by experienced drivers, tends to really make a 4wd have so much instant steering when least expected for those new to 4wd that it's just a hand full and very discouraging.

The other side of the throttle control coin is having a throttle curve that, for whatever reason, the car doesn't move until you're 1/4 in on the throttle, such as with a castle controller and a sensored motor. Usually this can be fixed pretty easily.

My strategy is this:

Linear throttle profile (resist the urge to use expo)! No drag brake. Gear up until it gets to temp after 10 minutes (160-170F). Adjust throttle epa down till you can handle it. Adjust brake epa down until you have just enough power to slow down for the most aggressive parts of the track.

Seriously. Throttle/brake control/feel is just as critical as tire selection and ride height.