I currently have a 700 P in 7mm RM. It shoots the 140-150gn stuff .5" or better. I'm currently trying a box of 168gn Bergers with no luck (in my opinion) so far. It shoots these about 1.0" @ 100yds. Haven't shot them any further, they may be printing 1.0" @ 400yds. Don't know, but I don't like the 100yd groups. Remingtons heavy barrel modesl are usually pretty good right outta the box, with little to no tweaking required.
I have owned two 100FP's, one in 7mm RM and the other in .223 Rem. The 7mm shot .5" and better. Traded it off for something else and never did any serious reloading for it. Never did like the Tupperware stock on it. I did paint that, though. The .223 I had shot awesome. I and some of my shooting buddies shot groups in the .1's and .2's regularly! I shot the 55-69gn bullets in it and it shot all those great.
The Tupperware stock's are cheap, period. I would think you could re-inforce it with aluminum dowels and bed the action (usually comes pillar bedded). If it doesn't come with the AccuTrigger, then you'll want to put an aftermarket onner. I usually chose Timney for mine. They're inexpensive, easily installed and work.
As for barrels, you can buy other barrels and different bolt faces for the Savage and change calibers rather easily. Check out Savage Shooters Supply.
I have always favored the Remingtons, but Savage builds one fine shooting rifle usually. As my Daddy used to say "The choice is yours, make it lite on yourself"....JohnnyK.
"The only thing necessay for the triumph of evil is for good men to do nothing."