I did mine on my '98. On that year, at least, the plug/grommet did not provide any better access to the top mount. I found the tool that worked the best to remove the top nuts was a flex head ratcheting wrench. Of course, the nuts for the Koni FSD's I put on were a different size than was used on the factory OEM, so I had to buy two such wrenches.
I did notice a difference in handling when replacing them and the steering damper (which I replaced at the same time and is very straightforward to replace). The old/original ones were well beyond their use by dates, though, and not representative of how they ought to have been operating.
I did have a little bit of difficulty keeping the old shocks compressed enough to remove them; I ended up jacking up the corner (to compress the shock), looping some iron wire through and around it to keep it from extending, and then jacking down and moving the jack to the frame proper to let the rest of the suspension drop and release the shock. There's no similar problem with putting FSD's in as they do not have any spring force in them--they only damp.
The rear axle shocks are super easy to replace.