Hello Bubba622
I bought a B&B cobra with the same rear suspension set up as yours, with the same problems. I was going to replace the rear Cargo Spring set up with coil overs. After researching...There was quite a bit to do and not just swapping out one for the other. I would have to move my brake lines, Fuel line and have some brackets welded to create space for the Coilovers.
So I ended up replacing the Cargo Coil with new Cargo Coils for now. If you go this route.
The Brand you want to get is Moog Cargo Coils part # 8558. The new Cargo springs will be really stiff at first. They'll relax after a few miles but I decided to have a shop cut a little off to lower my stance.
Cargo coils I bought.
http://www.oreillyauto.com/site/c/de...?keyword=cc823
I did convert the front suspension to coilovers and really like the results. Very comfy.
http://www.summitracing.com/parts/HAL-MS301-08375/
You will also need to purchase these wrenches to adjust the coil overs.
http://www.summitracing.com/parts/HAL-T114W/
I hope this helps