Ginetta G15: the Imp-powered baby GT the taxman killed (1968-1974) The Ginetta G15 was a tiny, light, rear-engined glass-fibre coupe built by the Walklett brothers in Essex around the all-alloy Hillman Imp engine, sold in kit form to dodge purchase tax, and the most successful of the classic Ginettas before the 1973 VAT change ended it. A guide to the history, the cars, what to look for, and what they are worth.