Nils - the VIN is the Vehicle Identification Number and it's located on the
dashboard on the driver's side, viewable from outside of the car looking
through the corner of the windshield.  Here's cool tool to decode your VIN:

http://www.analogx.com/cgi-bin/cgivin.exe

Look for the 5th to the last digit for the W or X or Z.

I'd disregard the talk about flywheels flying away.  The flywheel does need
to be the right one for your vehicle and that is a bit complex.  There are
different flywheels for standard transmissions and automatic transmissions,
and there are different ones within those two categories.  Stick with your
series (W,X,Z) and you will likely be ok - but you can also double check
that with the dealer.

Swapping the engine out on a vehicle of that age is pretty straight forward.
It's more brute force than black magic like you'd find in today's cars.