Re: .338 Lapua vs. 338 Lapua Improved
Who is your gunsmith and how is his familiarity with savages? I ask because savages don't need truing like a Remington does. It has a floating bolt head so truing and/or lapping the lug is useless. All a Savage action will benefit from is a ptg replacement bolt head, polishing of the cocking piece and cocking can, polishing and timing the extraction cam, installing a bolt lift kit, and replacing the POS accutrigger with a SSS competition trigger. All of this can be done by you.
All the effort to go Ackley improved outweighs the benefits unless you will never shoot less than a mile, IMO. But id still go with that lija barrel. A precision reamed custom barrel will shoot noticeably better than that factory barrel.