The main draw backs that I can think of are:
Would take away funds from your "personal" car fund
You'd have some people who are really into it, and others who mildly contibute, and then some jackass who is just a memeber of this site and goes around trying to take credit for something he's not involved in
positives:
Two heads are better than one...and if you had a whole site of enthusiasts building one car, holy SHIT!!!
Would be easier to get sponsoring
Would be a great way to get people more invovled (which is prolly just a chick thought lol)
I dunno.....I'm talking out my ass...as usual lol Lemme know what your opinions are on this