The Customs Service bought a ton of the Cherokees in 1987-88 to bail out Chrysler. We had the same problems with the CPSs, and motor mounts. The 1997-99 models are considered to be the best years for the Cherokee xj. Mine has been rock solid so far, of course it only has 122,000 miles.
I know it is late, but use speed pass and make an appointment. Twice last year I had to use DMV. Both times I made an appointment and arrived 15 mins early as they suggested, one was to renew my drivers lic. And the other was for reg. of a truck I bought from a private party. Both times I was done in less than 20 minutes.