I never even gave the fact that mopars had the elliptical set-up a thought , but yes there is that fact also. As far as clamping the springs the purpose is to make the spring more stiff to resist wrapping. I do not recall if your supposed to clamp the fronts, rears or both, I just recall reading about it in the Mopar Chasis Handbook (DAMNED fine piece of writing that ALL mopar owners should have) I didn't bother with clamping my springs because I drive mine daily in the summer and I dont want the harsher ride it causes.
The pinion snubber is designed into mopars to do what slapper bars do for chebbies, prevents the axle housing (and the springs that are attached to it out on the ends) from wanting to rotate or "wrap", it does so by physicly contacting a plate under the rear (you'll see it just above the snubber on the floor of the vehicle underneath. From the factory there is so much space between the snubber and the floor it isnt very effective at stopping spring wrap, it does it, just not as well as the adjustable will when set correctly. The idea behind the adjustable pinion snuber is to give you that instant hit by adjusting the snubber up so it is within an inch to half an inch from touching thus preventing any twist. (If I recall the automatics are supposed to be at 1" and manual trans are supposed to be 1/2" to 3/4") This setting is for race only though, I wouldn't go driving around town with it set tight like that because it will hammer the hell outta the floor and the little rubber snubber WILL mash out and be no more (ask me how I know :twisted: ) But I assure you, you WILL notice the difrence it makes, and you wont have gaudy ugly pieces of steel hanging low to drag and hit stuff and other wise be a general nuisance for little to no return in performance.
