I think you should be able to tune cars' suspensions because in the current version of the game (3.02) the suspension isn't stiff enough and your car leans every time you turn. Also, I think you should be able to add negative camber and change ride height. I know it's still in Alpha, but these are just suggestions.
The suspension stiffness is realistic atm. Also, all what you want to do can be accomplished by editing the jbeam files for the suspension.
You can definitely adjust the suspension. What's there is realistic for a road-going car, but if you want something more track-focused, you may want to make some adjustments. Play with the values for precompression, the coilovers and the dampers.
