I don't think it's that easy. On the 1600 I have replaced all the rubber with nolathane, but have been very careful to base my replacements on the density of the urethane and how it correlates to the rubber.
Some urethane is too hard, and you have to specify a softer version. The other difference between rubber and urethane is the compression. Urethane is more linear and rubber is more exponential. (I think I got that around the right way? - it's been a while).
Also you have to make sure you grease them up properly otherwise they will squeel and graunch.
I am running SuperPro on everything except for the diff moustache bar (Whiteline) and Nolathane on the castor bar/radius rods. These particular bushes available (not the brand) are softer in durometer than the superpro bushes. Fortunately I have a friend who used to work in the automotive industry and he had a fair amount of experience in bushings for driveline.