Camber
I have been looking around these forums and have noticed no one has attempted putting camber on a hot wheels car. It would give the car less traction and, if it has enough negative camber, rubbing against the side of the track would not slow the car down because the wheels could roll on the side of the track. 
Now I know this looks a little outrageous but I rather performance than looks. Soon I will test this theory using two of the same cars (2012 ford mustang laguna seca).
Discussion
Don't the wheels have a slight conical shape? The diagram above is super extreme, but I'd like to see photos of a car you can get going fast.
friction.... if you camber the axles gravity will PUSH the wheels out against the conical axle ends... far more friction.
but feel free, the sloppies need any help they can get....
Yep, a couple good arguments above for why that should not work. All the more reason to make it work! Let's see it!
That's some fancy science right there Sounds awesome to me...just be sure to post some photos once you get your Mustang rolling.