http://www.bmw2002faq.com/component/option,com_forum/Itemid,57/page,viewtopic/t,313667/highlight,turbo/
Check that one out...
Badasssssssssssss.
To bad you only experience that 335 hp for like 2 seconds. but its better than what stock is so, what the hell.
Basically, (someone correct me if im wrong here, but this is my understanding) EFI turbo's or Fuel injected turbo's are gonna have a more tunable powerband, and the power delivery will be smoother and cleaner.
The carb'd version, as seen in that link, will have a more abrupt power curve, and (again correct me if im wrong) adjusting air/fuel and other mixture settings will be more difficult.
But, it worked for the touring. And like it has been said before, ANYTHING is possible with money. Along with time and patience.
HTH,
Chris