The replacement passenger side bush is polyurethane so it does not really need any lube.
The bearings once packed with grease should stay packed. The top bearing may actually be better lubricated with grease than it would be relying on oil splash.
The rack teeth will hold grease so there should not be a problem there.
I expect that main thing that kills racks is lack of oil due to a damaged boot which is less of a problem with grease. I suspect that this is why many modern racks are lubricated with grease and I am yet to find a professional rack re-builder that uses oil.
Yet somehow I would still feel better if my rebuilt rack was filled with oil.
Edited by ls2lxhatch, 13 February 2012 - 11:40 AM.