HAH! Awesome BrianG!!! I was going to do the same thing with my emaxx truggy conversion, before i went with a 7XL setup instead.
Here are a few of my notes:
THere are few motors that suit car applications (outrunners), HOWEVER, one of the few that i found that would work very well is the newly released E-Flite Power-46 outrunner motor. It's an 800-watt motor, here are specs:
-Up to 800 watts of power (continuous, maybe, for airplanes, constant load...)
-670 kv (RPM/V)
-0.04 Ohm Resistance
-voltage range: 14.4-19.2 (4-5 LiPo's)
-continuous current 40 Amp, max current 55 Amp
-6mm shaft, so you can machine it to take a CV shaft (also reversible)
-290 g weight
-Diameter: 50mm, Length: 55mm
http://www.greathobbies.com/products...d_id=EFLM4046A
This motor on 4s LiPi pack should take a typical 1/8 buggy to 45mph direct drive. Or 55mph on 5s LiPo pack.
This was the setup i was planning to run, however i did not know enough to actually take out my wallet. I have no idea how hot the motor will run, and also you have zero flexibility as far as gearing (fundamentally). If you want to try that would be cool though ;) Also, on one side of the motor you have to mount it with 4 screws, and the other side will ride on a bearing, you can also take the shaft out and make a longer one to make it work with 4wd setup.
The E-Flite Power-46 motor is $130.
This setup would be VERY quiet. Almost inaudible, besides the tire noise.