Attached is my setup from the outdoor regional at NECRC (Durham).
The track was grass though it was very worn in places. The car was really stable and excellent into all the corners, traction zones you had to be carefull picking up the throttle but I think everyone had to. If it was higher grip red springs on the back might be helpfull. For more steering I would have dropped a spring on the front.
Couple of great pics from Tel showing how flat the car looked through the first corner
http://www.telsshells.com/DSCF4072.JPG
http://www.telsshells.com/DSCF4174.JPG