It all depends on what you like and how you dtrive. I tried both the 4600 and the 4300HD and went back and forth a few times. I prefer the 4300HD even though my times are about the same, maybe a little wuicker with the 4300. It is not overkill and runs excellent in the SCT410. Yes the current limiter takes a little bit of the torque away but its only at the very beging of the curve, after that it's all out. The 4600 winds out down the straight, the 4300 is all out down the straight. Does it strain batteries? Sure, but so does the 4600. I have no problem running my SMC 7200 70C packs with either motor and if all it takes to run the big motor are some $65.00 batteries, sign me up everyday.
I also have the SC10 4x4. It keeps me entertained while my Tekno cools between races. Thats about all it's good for now.