What is it about the factory stock you want changed? LOP, an adjustable cheek piece, more/less weight, or do you just want a pillar bedded stock? Pillars can be added to any stock, so you don't "need" an expensive custom stock unless that is specifically what you are after. Speaking in general terms, the less expensive the stock, the greater the benefit of adding pillars.
I want a free floating barrel but the cheap stock on this gun cannot be free floated. The stock has 2 ears on the forearm that support the barrel to prevent the barrel from dropping down into the barrel channel. It is the worst stock I have ever seen.
Clean with aerosol brake cleaner BEFORE sanding. Grind up the surface and if motivated, cut or drill shallow holes at various angles. quality epoxy steel WILL stick.
You can do some very nice work with these plastic stocks. are they perfect? No.
can they let your rifle shoot as well as it is capable? Yes,
Pillars are installed so that the action bolts do not squish the stock - no more no less.
If the stock is made from a compressable material ie composite, lam or natural wood- pillars are a good idea BUT they do not need to be these big hunks of steel. Thin tubing is more then sufficient.
Proper bedding is critical to holding the action and stock in the proper orientation. ALL factory stocks can use some help - your action bolts are not designed as load bearing devices. that is what your recoil lug is for.
For hunting, I actually prefer the factory plastic stock - at the least the Savage ones
Jerry