I didn't do much, but I really didn't like the weight balance of the rifle or the look of the synthetic stocks on my Sportster in .17HMR.
Before:
So I swapped out the synthetics for a pair of cinny lams to match my .308 Ultra. I like it much better now. Much heavier, better balance, free floated.....it goes on and on. Bottom line is that it's a much better bench gun now, and the groups are tighter. Which is saying a lot of a caliber that's tight to begin with.
After: (.17HMR "Ultra Varmint Wannabe" on the left, .308 Ultra Hunter on the right)