Soft rear foams
http://www.racing-cars.com/pp/New_Ca...Aero/JY35.html
and hard fronts
http://www.racing-cars.com/pp/New_Ca..._SV2/JY45.html
You will find much better handling on foams, and they will last forever compared to pins.
Various techniques for mounting them on the wheels
http://www.oople.com/forums/showthread.php?t=150120
Alternatively, if you want to stick to rubber the Schumacher Venom in white compound will give you loads of grip on the rear.