If you want to put up a donations site, I don't see why you can't. But I don't see a donation site for a Porsche getting more than $100-200 at the most. Randall even says, "I didn't get tons of money," he said his wife donated most of the money.
The girl that set up the site to get rid of her debt had a story people could relate too, most people aren't going to sympathetic to a guy who wants a Porsche.
You might also want to consider the cost of buying a website and paying to have it hosted. It would be fun to see if anyone gave you any money, but in this economy I wouldn't count on covering your hosting fees.
It's a good idea but I think that if you seriously want a Porsche there are better ways to get one that asking for donations.
Just my $0.02! Good Luck!
