James,
My set-up is a stock 26cc CY engine, Samba F1 pipe, Oddified ECU, stock clutch with red HPI spring, limited slip diff in the front, rear diff filled with 500K cps oil, blue compound MCD on road tyres.
I normally run a roll bar at the front, with toe in at the rear and toe out at the front and set the ride height as low as possible.
My gearing for the track is 30, 33, 26, 23 and if I use the mini-moto/kart track change to 33, 30, 26, 23, although 33, 30, 25, 24 would be better but I'm waiting for the release of the 24 & 25 gears in steel.
The car was even better on tuesday at the track and all I did was increase the pre-load on the rear shocks.
I would guess that your engine has plenty of low/mid range power/torque so try 33, 30, 25, 24 and if the initial acceleration is poor swap the 24 & 25 gears around.
What clutch/spring are you using? The red HPI spring makes a significant difference on a high traction surface such as tarmac.
Clive