This is my response to the challenge on the MINDSTORMS Forums.  The challenge was to build a racecar with a suspention. 
Well, here it is.  The supention is homemade due to my lack of shock absorbers.  I used some wire to make the spring.  
Unfortunatly, the homemade shocks come into play very little.  I ran it on my driveway (see vidio) and it wnent just great.
Overall I am very happy with the results.

uses:
motors 5x
RCX 1x