Tires are whatever the fast guy is running.
There's more than 1 battery holder?
Tplate, snug screws so it doesn't flop around.
ride height 2-5mm, whatever doesn't drag and matches the front.. Higher if it's the 15th av ed. You don't want to scratch it.
If you want to get really technical you could try running washers instead of Orings in the T bar...
It's an f103, it will handle 90% the same no matter what you do to the car...