nice job mate.
i did a chassis similar to this, the only problem i had was the steering become very light when the battery was layed out across the chassis. you'd be better using a saddle in there. another thing you may want to consider is around 45grms up front of the chassis.
if you get trouble with the rear traction, a trinity 3deg pivot block will help, you may find the car will seem to have more turn-in at the rear.
let us know how it goes.
