How to get more grip on a wooden floor?

[rhbmcse]

Pretty self explanatory title!
We race on the above surface and grip is an absolute swine.
Im running a TT02 at present (not for much longer).
I've removed grease from both diffs, changed tyres to yellow pins.
Rebuilt the shocks (hop ups) with the softest springs I can get.
Still zero grip.

Any ideas folks???