I could be wrong here, but I don't think there is a difference as I suspect that the ultra is just branding on the two wheel drive 2.0TDI engine, and they are all that.
Engine wise you can get a 2WD 2.0 Ultra manual or S-Tronic, the 4WD is the 2.0 quattro S-Tronic.
Trim you can get SE Executive, S-line or Black.
Best to check with a dealer