your best bet is what everyone i know is doing at the moment, buy a 1.3 bonus escort, stick a turbo lump in it, dont tell the insurance company,

...or go with a insurance company (normally c.i.s) which lets u drive another car as long as its not registered to you, buy a 50 quid 950cc fiesta, insure that, buy a cossie, register it in your mates or parents name and there u go.done it for years.