The UAD stuff is great (I have 3 cards and have bought several of the optional plugs), but if you're specifically looking for "colour" (whatever your definition of that is) you should be able to get that out of the input stage algorithms in the URS CSP plug.
The UAD plugs are very musical and easy to dial-in great sounds with, but they won't work any mix miracles. You should be able to achieve great results with Waves & URS plugs.