When I was preparing (mainly, reading the Chilton directions) to do ours, it seemed pretty straightforward. The Chilton manual instructed to drain the tank, but being the reservoir is on top, I thought that may not be necessary. Did you drain the tank, or leave it?
I didn't drain it, but it was only at about 30%. If it had been nearly full, I probably would have siphoned some off first to keep from splashing it all over the trunk area. I don't remember any tools used inside the tank, so no worries there, but I did give them a rinse afterward just in case of any stray fluid. I found a flathead screwdriver that had been in the box with the old fluid-covered parts and didn't get rinsed, and it was rusting like it had been buried in road salt.
The repair is really straightforward. It involves removing some wire clips and zip ties, which you can just cut, since the reservoir comes with new ones, disconnecting the wiring harnesses, taking three screws off of the pump, unscrewing the ring that secures the reservoir, yanking out the old reservoir, and reassembling. The biggest hassle was actually getting the reservoir out of the tank. It snaps into a couple of anchor points in the bottom of the tank, and it can take some force to remove it. I think that step took more time than the rest of the repair combined, as I was afraid of breaking something or splashing fluid everywhere, but also needed to apply enough force to get it done.