Ha ha, 'why not' is probably the most obvious answer, especially if you happen to have an old Porsche and a helicoptor jet engine gathering dust in the corner of your garage.
I recall seeing (in a car mag in the early 90's) a jcb that someone had replaced most of the steel bodywork with fibreglass and fitted some massive V8 to. It could pull wheelies and blew flames out of its exhaust pipes. . Quite funny though.