Your scope choice will have a significant impact upon whether you can make weight with the Winchester. If you are planning a LRHS weight category scope, make life easier and go kimber. Otherwise, either will work and you already know the cost differential.
300 wm is where I start to really notice recoil. I think the kimber is a fantastic stock, but the 300 wsm is about where I draw the line on the 8400. 300wm and 338 wm really get my attention in that platform.
Keechikid may weigh in as he bought a very nice 300 wm in an Echols legend here a few months back which met your weight criteria. If I were going m70 and had time to wait, that is the route I would go (legend in edge.)
