William,
Last summer I rebuilt a 1982 300D-turbo engine plus the turbo for about $1500. I got a good price on new Mahle pistons $95/each. The head did not need any work and the injection pump was good. The machine shop bill to remove the old sleeves, install new sleeves and bore for pistons was $175. These prices do not include any labor(all mine).
You should be able to get most of the parts from the Shop Forum. If not, let me know and I'll send you a list of half a dozen places you can get parts.
Bill Lewallen; Lexington,Ky. Where diesels purr and turbos whirr.