[beetle1303]

it could work...
my major concern would be on the suspension though. toooooo big wheels and to low profile tyres. it isn't the best combo imo cause it will probably reduce suspension travel a lot, and give you a very harsh ride. i would try to get tyres with less difference in width ( personaly im planning on running 225/40 18 and 285/40 18 and then going for 265/40 at the back as max). I dont believe that there is any point of getting widened fenders first and trying to fit everything under. Im going the opposite way, leaving the fenders last. As stated you will need major bracing at the back and it would be wise to try and tie the back into the rollcage if not going for a tube chassis.
Also you need very precise calcs for wheel offsets, and keep in mind the increase in turning circle, due to wider tracks.
Cost... If you have the money, sky is the limit. the only thing is if you believe that its worth it.
The problem is that you could spend enormous amounts of money and still don't get there. The drawback is that the beetle is an old design, revolutionary at its time, but lacking many features of modern chassis technologies. Also remeber that even if you find a low mileage car, it will be at least 30 years old, and its not the same with a new chassis... Fatigue evelves through time and considering your req's for the project, the car will deteriorate quickly. Dont get me wrong. the only car I have is a 1973 1303 and wont change it for anything...

Chris