Edited: 10/1/2008 7:45:18 PM by 4PUMPED
As far as your setup, you could totally delete the coil, and run an accumulator, and go to a higher size cylinder to compensate for the loss of the spring.
As far as the ride, It'll be a total change.
Maz Duh is right...you would want a 1/4 coil or lighter. The orange ones in the pic above are 3/4 tons and still too stiff. If you want coils, run some civic fronts...those work pretty good for the rear of a truck, but they'll have lots of movement, even with accumulators.