For $300 I'd be all over it and leave it as is! Like Acloco said the magazine is gonna need some work to get to work well for the 708 round, yes it will work but I sure wouldnt expect my wife to like it.
If however you proceede there are a couple of things that might help.
A 7mag barrel would be a dirrect swap and shooting 120 grain bullets or reloads could get it to 708 recoil.....For that matter you could reload the 300 WM down.
Most of the factory 708 barrels are going to be 1/11 twist, not realy a problem as the 120 grain bullets work great in the 708 anyway.
I for one would swap you a .473 bolthead for a .532 .....Depending on if its a small or large fireing pin?
Carefull as this Savage swapping stuff can be very ddicting