The inners are not difficult, especially if the outers are already off. Unless you have a solid reason to distrust the shop, I'd give them the go-ahead.
But, like Reagan said, "Trust, but verify". Ask to see the removed components and ask for an explanation (if you need one). I replaced my inners recently because the outers were shot, but the inners probably could have been left alone.
1. Make sure you have the right replacements. There is a lot of confusion in the aftermarket about what parts belong on this car. I have some horror stories in that regard.
2. Use a utility knife to cut and remove the old boots
3. A pipe wrench works very nicely to remove/replace the joints (can't believe I said that)
Like everyone's saying, not a PITA at all. Careful use of a large hammer helps get the outer out of the loop on the knuckle. I used a large pair of channel locks for the inner. The hardest part was getting the new boot over the end of the steering rack and that wasn't that bad. Make sure the nut on the new inner tie rod is on the same number of turns as on the old so your alignment won't be too far off for the drive back to the shop.