and what you are talking about is the difference between half assing it and ...you know...building something where you actually know what you are doing. You can get 500hp from a variety of motors, why pick the one where it will be so overstreesed it won't be reliable? Also busa motors are not cheap, and it would cost more to get one to make 500hp than it would for you to rebuild your saturn motor to make 500 hp. There is dare to be different and dare to be stupid, putting a motor designed to haul 1000lbs max into a chassis that weighs 2400 lbs is dare to be stupid for more reasons than I care to list right now. It isn;t hot rodding it is just making a jackass out of yourself. Honestly, talk like you have done something and not like some 18 year old kid with too much enthuasim and not enough intelligence, at least act like you know what you are doing even if you don't.
The people who bult the busa smart cars or busa powered anything - I can gaurantee you they would have picked a different motor had they the chance, a lot goes into the thought process before someone builds something custom like that, they didn't just do it because it was a busa motor, more likely they did if for packaging and weight concerns. I am sure 1000 measurements were taken before a donor engine was even selected.
I am not trying to dissuade anybody from trying something different, I am saying that if you are going to do it be smart about it, don't just be some jackass who says "we should stuff X into Y cause that would be cool", the best executed projects have a goal and though process behind it.
to bring this back to the current project at hand....cafe2b....don't be a jackass. You are new to bikes, learn the bike you have first before you delve into something that is clearly over your head. If your buddy wants to do his sport bike swap into an older chassis or what have you, formulate a plan. Don't just do it "'cause you got $#!+ lying around" or all you will end up with is $#!+ bolted together.