Fortunately, I have a "fixer", who is extremely familiar with these vehicles (it's basically all he does), so he would be able to get me some proper units, and would be well aware if I am being overcharged. Indeed, just looked at his site (that I built for him), he does have a replacement unit for sale for ~800 euro (with VAT).
Good! Have fun, you'll learn more about your DS than you ever wanted to know. I've rebuilt a DS bit-by-bit while it was in use and I would have much rather had the time to do things in a more planned manner. Engine rebuild is a nice chapter in its own right, the 21 is the best engine and you could get a junked engine and rebuild that at leisure, they are very doable.
