If you have a leveling kit like Eibach or Bilstein and you add an aftermarket upper arm with a uniball, does the ride improve?

 

Depends how much lift you have, but the idea with a 2.5" or more the UCA replacement will return some of the ride quality you're missing.
It's not magic, but may help a little. If you have 2", the UCA isn't needed and therefore probably not going to help.

I do not know what is on the market, but the UCA would need to be longer than factory to make a difference. Swapping brands for the same spec as OEM will not be helpful. The UCA and LCA are fighting each other causing lessened ride characteristics. Extended length UCA helps the two control arms play nicely together.

 

Thanks for the info!