Try this for a 'lightweight set-up'
It should be very close to what BT and Pudge are using...
Last sheet I saw they had a slightly longer wheel base with 1/2* rear toe added on the hubs. Also a full length rear spring, but for the grip of my track, the cut spring stablized the car out a little more.
The total car weight is 53.1 ounces. ROAR minimum is 52 ounces.