IMHO the stiffer springs such as the 906 OMEs help with lateral stiffness of the trailer in compared to the stock springs. The 881s are used in front to offset the rake caused by the 906s. Members usually replaced their shocks at the same time. If you get the suspension bug though, only your wallet can limit your choices so to speak.
There are many threads on suspension. Many of the supporters of this site sell OME products. Click on them and just take the time to look what they have to offer.
Ever tried running 20 psi or lower at the ramp? My buddy had a 2wd long bed Ford 250 and would spin tires pulling a 22ft CC up an algae covered ramp. Sand, weights, etc. in the bed did little for him. Ultimately a locker (can't remember the company) was installed and it was as if he had a new truck. Pulled up with ease. It may be something to consider for the future.