You can get injectors and heat shields from FastLane for $324, and a cheapo Harbor Freight Diesel compression tester for $25. Factor a deep 27mm socket and torque wrench if you don't have them, some injector line clips that are missing or you'll break...

My guess is the shop figures 3 hours in labor at typical non-Bay Area rates.

The tech won't get rich off you but there should be a net profit in the deal.

Sixto
87 300D