[Shannow]

I've not had a problem with rear end grip so far - the car is very light (1.35kg) and has a 33/66 front/rear weight distribution now and seems pretty well balanced. I use velcro to hold the battery in place with the strap to stop it bouncing about - so I can adjust the battery position further back to adjust the balance if required.

I've only just started using it outside (mainly used it on medium to high grip indoor surfaces so far) so it may get tweaked further.