I have upgraded all of my Savages. Only once did I replace a barrel, and I regret doing it when I did. That original Savage factory barrel could ring the gong on the 1Km Steel Silhouette Range Buffalo at Whittington, ten straight. It had less than 600rd through it. It was given to another 'Hider.
Reasons for replacing a barrel: Accuracy has dropped off suddenly. I want to rechamber to a different cartridge. There are maybe others but my feeble old mind can't quite get around to them. Never part with a barrel if it still shoots good; good lesson learned the hard way.
Other than that, all I have changed is ergonomics, and for me, that's a must; I'm 6 1/2ft tall and 13"LOP just ain't gonna get it for me. The bolt is up against my nose. I spend what I must and no more. Choate makes the stocks I buy, I also have a McMillan, but that's another story, and I am eternally indebted to McMillan for their kindness and generosity to SH, and by extension, me. Choate employs stock extenders that mate with their Choate Savage Tactical stocks perfectly, My rifles use 3 each.
Optics are a horse race. I outfitted all of my LR capable rifles with one particular BDC scope design that I could afford for about $300, and immediately after, the manufacturer dropped them in favor of something only vaguely similar and costing a $K. IMHO, I prefer the older one; If I can range it, I can hit it without touching a knob. Not so with the new one, knobs get turned, period. I have no scope to personally recommend.
The Accu-Trigger is OK for me, the extractors have only ever failed for me when I ran my charges too hot; and if bolt smoothness and cocking force send you wailing into the wilderness, I say, "Keep going...".
I won't buy/build a yacht if a rowboat will get the job done.
Greg
ETA, the Savage is an accurate, affordable armature upon which the hobbyist can append accessories that improve ergonomics, accuracy, and even reliability. My Savage LR capable rifles 223/308 each cost under $1k (includig Optic) when finally updated to their current status. They were assembled on Savage 10VT <$400 rifles purchased with the Savage customer rebate. They are/were never intended to win against the big boys, but, instead to provide a learning/training tool that was fully capable competing in the intended competition (F-T/R). In that goal, they have succeeded, with the 223 competing in SW Region Nationals at Ben Avery Range (Phoenix area) MR/600 F-T/R in 2017.