Don't pay someone between £1550 and £2500 for a job that you can do your self for less than £300 and probably even do a better job of. It's a really simple task. I refurbished (not totally re manufactured) my 1986 2.5 N/A not long ago, including cylinders deglazed, 4 new pistons and new bearings all around and there's a noticeable improvement, so technically my engine is back in "like new condition".
What you will need is a good weekend (ie. Friday evening, Sat, Sun and a bank holiday Mon if you can) as well as another car so that you can go and get all the bits that you need (which you wont know about until you take the engine apart).
It's actually a really simple process:
1) Unbolt exhaust / turbo and air intake manifold from cylinder head
2) Unbolt rocker cover
3) Unbolt rocker shaft (all as one)
4) Pull push rods out (simple slide them out of their holes)
5) Unbolt the head and lift it off
6) unbolt the sump
7) unbolt the piston big end caps and then knock the piston up and out!
All of which can be done in situation without having to remove the engine. The 200 tdi is only slightly different to the 2.5 N/A so the 300 shouldn't be all too different either, perhaps a few extra wires. I don't think that there is too much difference in terms of general structure. Generally speaking the only parts that you will need are 4 piston ring sets (or 4 new piston heads with rings already in place if your current pistons are damaged), 4 new bearing sets and the tools which are a cylinder deglazing tool (which attaches to your drill) and piston ring compressor, all of which should cost you no less that £200 at the absolute maximum.
You'd save your self a hell of a lot of money (ie. between £1000 and £2000) and you might find it really good fun. There's nothing like starting the engine for the time knowing that you've done it yourself.
Would you like to know more?
-Pos