Grant,
There is a lot more work on these than there is on a '98, depending on the calibres you want to go to. Anything based on an '06 case would not require much if any feeding work, other larger calibres will need rails opening, bolt face opening (except the P14, which is already magnum size) and mag box work. My 450 Ackley is cut down to look like a Rem 700 on the action, and 700 mounts were used.
Any smart gunsmith can cut down the back of the action, and mill the bottom off the rear base to make it level and fit correctly. The barrel is a square thread, but that's no more difficult than rebarreling anything else. All of mine have been converted to cock on opening, something mandatory in my opinion, and have had faster springs fitted. The bolt on the 450 has been replaced with a checkered straight one.
If you are right handed (I'm not) the dog leg bolt can often whack you on the fingers on the bigger calibres, so that would need to be replaced.
Lyman and Redfield made receiver sights to suit, in fact 98 receiver sights fit fine, as do Springfield sights.
All mine have either Timney or Dayton Traister triggers as well. Don't be fooled into being told you have to have a Dayton Traister trigger with the cock on opening kit, Timney's will work fine.
There were 3 makers of M17 actions, Remington (1st choice by most people), Winchester (2nd) and Eddystone (3rd). The Eddystone actions have often received bad press from various sources, saying they are brittle. My 500 is on an Eddystone action, and I have never had any problems with it, nor did the gunsmith when he made it. Personally, I have no problems with Eddystone actions.

This is an action pic of my 450 Ackley, shows the bolt and the cut down action.

This is a pic of the 500 Jeffery, not as close up, but the only pic I have at the moment.