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
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.
AJ