Helem V6 - built with Renault's permission to use the Renault Spider as the base, with the intention of it being homologated for racing, complete with the PRV V6, instead of the standard 4-cylinder Clio unit.
Random Fact (probably v. well known by now), but the design Pinifarina created for the 406 Coupe, was actually proposed for the Fiat Coupe, but Fiat rejected it, and instead designed their own, whilst Peugeot accepted it for the 406. I'm glad it went that way TBH, as I love the way the Fiat Coupe looks, and actually prefer it to the 406 Coupe's design, which is by no means ugly.