Regarding the emissions question, cars that run on biodiesel have virtually no emissions. There are even biodiesel cars that can run on vegetable oil, however there's one major con...
YOUR CAR'S EXHAUST WILL SMELL LIKE FRENCH FRIES. LOL

I know that sounds crazy but here's and article to back up my claim.
http://moneycentral.msn.com/content/...ar/P115218.asp