Bill,
In my experience, which is a few years 4 sure, PS pumps rarely go bad. About all that happens to them is that they might start leaking, but even then that's typically well after 100 K. The reservoir is kind of cheapie tin can, so U can't lean on it, or hit it real hard w/o denting it.
Alotta the guys have replaced them with a peformance one from AGR in Summit. I changed my Box out, along w alot of other guys on the list, to a 12:1 ratio box, which is alot quicker. Also Mike Renz has been hosting a GP on upgraded, more rigid steering shafts. I got one and it looks like a good piece - see Group purchases.