I have been down that path. I was going to rebuild a magna power steering rack seal kit was around the same price. I pulled it out and I started to strip it down until I got to a 36mm Hex bolt that I couldn't undo as I didn't have the tools for such a large hex. Tried a dirty big bolt with no luck and gave up to much pain really. It is a complex process and chances are I would have stuffed the seal kit.
So I bought a remanufacterd one for $350 from bursons. Only $120 dearer and worth every cent. Also comes with a 3 year warranty which you work doesn't.
Add in the price of tools it would have taken to rebuild the old one (if you can find a 36mm Hex key) and the difference is minimal
Non power steering racks are a different story, work in the park in comparison.