Even with the shop labor, its worth every penny in both the quality of workmanship and the fact that its still less $$$ than buying a motorcycle that can be a comparable ride. Most of the guys i know on the "track" have motorcycles in the 30K to 50K price range ... the very competitive professional rider... heck i prices out quality USED track gear for 5 seasons at $4 grand that factors crashing into the $ math.
My point is that 20 grand (with the cost of the bike originally plus a full out build from carpenter is actually cheaper than buying a pro level bike apples to apple