agree with everyhting above, but there are a lot of people who do it. While i cant answer your question, and even if i could i wouldnt as what you are doing is putting you and everyone else on the road in danger...

Just some further food for though:

its defectable
if you have an accident and the assessor spots it (i know your thinking i'll just take it home and change the spirngs, but lets say you went for the cheapest insurer eg. AAMI, if its not drivable you dont get to take it, tow trucks are directed to take the cars straight to the AAMI centres)... so, if the assessor spots it you are up for the damage to yours car, and anyone else porperty including houses cars shops, telegraph poles etc...

Good luck mate