Yeah, paddles alone are close to $500 each. Plus, to do it right you should run them on the lightweight aluminum racing wheels which are another $150 each. I think my rear set was just about $1400.
Yes, you will use 4wd with paddles at the dunes. If you don't you are missing out on alot of fun. We play follow the leader in the badlands area. Keep in mind that paddles need to be spinning and you need a moment to wind up the rpms. Thus the reason for the light weight wheels. When coming around a sharp corner following someone in 4wd even without paddles, they can hammer it and get up a hill. In 2wd it won't happen.
I started out running a set of 32x14.50 Mickey Thompsons on the front with the 33" tall paddles in the rear. When I bought the vipers I noticed a "tremendous" difference with holeshots and the tight & twisty stuff. I also notice a difference when my ARB front locker is engaged or not. It all boils down to traction.
For you guys wanting to run taller paddles, be careful. Typically the taller, the wider. And unless you have whopping hp to turn a 35-37" tall tire that is pushing 20" wide you will end up bogging down. Keep this single rule in mind........ in order for paddles to work they need wheel speed. Just like bottomless mud. How many 4 cyl guys have you seen stick big mud tires on their rig & then not be able to clean them out? Same concept.
On that same note, I run 37" Iroks for trail. I'm running pretty high hp and low gears. I notice a trememdous difference in performance and acceleration using the shorter tires. If you can only afford the rears, find a junk set of shorter front tires. Sure, mine looks a little hokey sitting high on short tires............ but you can't catch me.
Jim