Both front and rears were a challenge due to corrosion on the shafts. I had to cut the shaft (below the top nut) on the rears with a Sawzall and break them off. I made the mistake of cutting off the strap that comes on the new shock to keep it compressed during the install (don't do that)! Once you get the old shock out, loosely connect the bottom and aim the top shaft at the frame location (be sure and put on the rubber washer prior of course) and then just cut the strap. Off it goes up into the top location.
Regarding the difference on a newer rig, all I can say is the difference on mine is huge. I think most chassis manufacturers only put on the basic shocks to save cost. Spend a few extra bucks and get good shocks, they will save money and headaches in the long run.
I got it done, it was quite the job but what a difference!!! I put on a set of Monroe Gas Magnum RV shocks and the thing handles so much better. No more lean and bounce. Not sure but the shocks on there may have been the 1998 originals, they looked like it. Anyway, thanks for all the posts and suggestions.