you may want to check out a company called dubsport in the UK as they do a LOT of dual engine conversions in VW golfs and rabbits.
http://www.dubsport.com/
http://www.dubsport.com/projects.asp some of their conversions on that link. It's a fairly common thing going on right now, mainly in the UK though.. Over there I know a twin engine bug being built, twin engine golf, twin engine caddy that was built over here, the tiburon (US again) *very nice guy whom owns it, if you ever get the chance/oprotunity to talk to him, DO IT. VERY knowledagable on the subject, as are dubsport. Great guys at the shop!!
I think your speaking about the twin engine tiburon setup, correct?
Ran like 10.90s on street tires?
EIther way keep us updated and best of luck to you.