shocks ???????

[tacoma man.]

over the weekend i went to Lowes to get 6 bundles of roll out roofing and 2 buckets of black mamy. anyway on the way home the back of my truck was sagged down bad, are the TRD shocks better than the regular shocks? and will they hold up better? and how much? i dont really haul stuff in my truck a lot, but i also had problems towing my wave runners, the truck was all over the road especially when i would hit a bump in the road. any suggestions or answers would be appreciated.

oh, the truck rides smooth and level when im not hauling or towing something. the shocks are great for highway travel, but suck when I try using my truck for what its sopposed to be made for. thanks.