As far as the numbers? It all depends on how patient you are, and how smart you shop.
$2500 for an SP5k? Sure -- if you get one NIB. But if you're planning to rebarrel, why would you even want NIB? I bought my SP5k used, with a small nick in the finish on the left hand side for $1800.
You could get a $400 B&T barrel. Or you could get a $170 RCM barrel. Ball-park on labor to install the barrel and refinish the gun? About $700.
So, the only way you're going to approach 3800 is if you buy NIB and go B&T. I got a heck of a deal on my sp5k, but I see used ones sell from time to time for $2000ish.
By my calculations, you could get a more budget oriented SP5k build going for 2900 or so.
But, like anything in this game, if you want it NOW you're going to pay more.