If I had $150 to spend on a stock and was a little mechanically inclined, I'd get one of the money saver stocks from Stockaid stocks
You will need to spend a few hours sanding/filling/painting, but it will be a MUCH better stock than the tupperware stock that Savage sends. If you keep the plastic stock as it is, you might be able to sell it for $25 or so.
To see the types of stocks that stockade sells, click on the price link.
As far as stiffening up the stock you have, its a lot of effort for very little reward. You can make sure the bottom of the recoil lug isn't touching the 2 ribs under it. And tighten up the screws while holding the barrel centered in the channel. In my opinion, thats about all the effort that the plastic stock is worth.