5 cylinder turbo diesels

At this point I am pretty interested in building an inline 5 turbo diesel. I understand how the diesel works and all for the most part. I'm doing research right now, and I'm sure there are others that are and have done research prior to this post. Basically here is the low down. Later in fall or winter I am going to pick up another audi probably a pre-96 one. Not quite sure what yet though. I'll probably drive that around for winter and then next year I'd be interested in swapping in a diesel. Here's a few questions...

1) Are there any differences between a gas & diesel short block in the way they are designed?

2) I know sizes can be different, but would using a normally "gas" engine block with a diesel head work as a diesel?

3) Is what makes a diesel engine a diesel engine in the head design (no spark plug holes?

4) If so, does that mean everything else is the same?

5) Also, I understand why diesel can run such high compression, but how do they obtain it?

6) Are there any 20v head (designed for diesel) that I can put on a 5 cylinder short block?

7) If audi doesn't make a 20v diesel (and if there is no way to make your own :wink: (by lets say sealing the spark plug holes>?)) Would a volvo or mercedes (if they made one, which I'm not sure of yet) directly bolt on an audi transmission? I know volvo is horizontally mounted so it'd fit different in the engine bay.

I'm going to keep looking things up, I'd thought I'd start a post to help with the search and for anyone else that is interested in a diesel.

Actually I guess there is another question,
Is there any limitation in turbo'ing a NA diesel (anything to worry about). Knowing that'd you have to have an exhaust manifold, maybe oil lines, or custom things built to accommodate the addition of a turbo.

Sorry for the long post. Thanks

8)