I just found out my 1993 100CS Quattro has a cracked block. This is the 2.8 V6, the 100 S comes with the 5 cylinder turbo. I am searching my options as to what motors will fit in there. My first choice is the 2.7T, then would be a modded 5cyl Turbo. Does anybody know?? Thanks for any help.

I too am interested. I have the '87 5000 quattro with the above mentioned 2.3 5 cylinder and may be swapping engines if I can find one. I'd like to go with a more powerful v6 or v8 ( I believe the v8 was in the later years...early '90s). Do they mate up to the same quattro gearbox?

it can be done look here www.germanautoconnection.com

Cool. Just a few motor mounts and a fuel system. Betting I'd have to splice a little wiring though.

yes wiring skills will be required

what about switching from the 2.3 liter to a 2.2 10 valve turbo, what would be required to do that? what kind of time would be involved?

Dipendes, if the 2.2 is mechanical, like has a CIS fuel system, then I do not see why the system wont be swapeble.
Though, having the original 2.2 wiring harnest would be beter idea.

PS. HOW da hell 2.8 engine cracked? What happened? you left the water in the coolant system, and the ambient temp droped below 0C?

it would take a while ... like already mentioned wiring harness will be required eather original or fabrication and also an ECU and the fuel will need tweaking