Sounds like you are on the right track. Trigger upgrade, and a stock upgrade w/bed job would be a couple of inexpensive (relative term) things to pursue in your effort to further shrink your groups. If you are holding to a tight budget, have patience as these items pop up for sale used from time to time on various sites.
Research your triggers well, as some may not be compatible with the newer X-Pro trigger guns. An example would be the Kepplinger single set trigger. This is a sweet trigger that could swap right out with the older Rem trigger. In speaking with a gunsmith recently, I learned that is no longer the case with the X-Pro. Timneys do well, but most prefer the Jewel.
After these upgrades, it is on to reloading. From there, the downhill spiral gets so steep and you can't get back out. You're addicted.
One more thought with the thinner contoured barrels on the SPS: Take a look at buying a SIMS Barrel Deresonator.
Cabela's: Sims LimbSaver® Barrel De-Resonator
I use them on all my rifles. These little gadgets helped close up my groups about .10 to .25 MOA on some of my rifles. On others, they had little to no effect at all. But for $10 + s/h, it's a cheap experiment. Keep us informed on how you are progressing.