I had +2 initially and when towing a 5k# boat it was not fun. I routinely hit the SVC bumps, even when they were in the high position. I didn't try them lowered to carry the load more. Even unloaded except Diamondback bed cover and other items in the bed I'd routinely hit the bumps. So, I upped myself to +3 Deavers and have been happier. Very plush ride unloaded with added compression clearance when carrying some load.
Deavers are much softer than stock and will rely on the shocks much more to control the movement (although this is a slightly erroneous statement, as more spring force - stock springs - technically require more dampening resistance). I've got Fox3.0, so I've got more tune-ability with compression zones, etc. This allows greater dampening deep in the compression and lighter dampening while in normal ride zone.
I never ran my Deavers with stock shocks, but I'd imagine they'd work well and provide a good quality ride.
On the stock springs, they do a lot of things well, but have to compromise in all areas too. If you find yourself towing a lot, they might be a good setup to stick with. Otherwise get a custom +3 pack with added leaf from Deaver to help. Or, buy a stock +3 pack, try it out and if more load capacity is needed add a Deaver leaf - kind of a pain, but at least a way out.
Hope this helps in some way.
