I think the car works better without using all the extra down travel you get from the new shocks. I limit mine about to where an older MBX5 would be. The major changes for the R are the shocks and towers, front lower hinge pin plate gives 1 degree less kickup, the ackerman plate moves the holes back a bit. They did modify the arms and chassis for more down travel also. The steering knuckles were also modified for more steering throw although you can dremel the old ones and get to the same place. If you get the shocks and towers you will be running basically the same car that Scott Hughes used to take 2nd at the World's.
The shocks are a huge upgrade over the old ones. The oil stays clear and the shocks stay consistent for a long time. The car is better in the rough even though the old car was pretty good.