If you upgraded fork with GVE/Intiminator, have you also installed fork brace?
Stock springs are not an issue for me both Sonic and RT calculators agree they are right for my weight. If they get updated it will likely be last thing on the list and only in case if front turns too soft in relation to rear.As GW said, the seals are just rubber rings. The bushing inside the larger fork tube limit side-to-side slop.
The damping valve from any supplier--Race Tech, Ricor, Cogent--is the last step to upgrading the forks. Any of these is a big help, but it isn't the first thing to do.
You need springs to suit your loaded riding weight. Changing the springs does only that. Otherwise, different springs don't improve anything else.
As noted above, the fork brace is important. Get one. Get the correct springs if the stock springs are not right for you (and they're right if you're about 165# or something in that range.)