Tikka Performance has some nice bottom metal/magazine options, and some nice bolt shrouds as well. They offer bolt handles too, but do not offer a swept (angled) version, which I prefer; I go to Glades Armory for those (be aware that some folks have had some bad experiences with Glades customer service, but I have never had any problems). Other than that, a YoDave or Tikka Performance trigger spring, and you should be good to go!
When you wear out that 300 WM barrel, you might think about going 300 PRC, as it's a shorter/fatter case which will let you run the heavier 30-caliber projectiles without intruding (as much) on powder capacity. There are a couple of barrel nut systems available for Tikkas now (Patriot Valley Arms, Southern Precision Rifles/Bugholes), so you can get a barrel, get a headspace gauge, and install your own barrel (saving you time and a few dollars).
I have two Tikkas with a third in the works. Love 'em.