The Ariel Atom is a Honda-powered, open car with only as much hardware as needed to keep the thing stable and fun. All other structures have been sacrificed to the gods of speed and agility. Its light-as-a-crumpet comportment gets going by way of a 2.0 liter i-VTEC motor, hooked to a six-speed manual tranny, and, to the delight of trailerless track-day denizens, it's street legal (at least in the UK). As this video shows, it's also pretty good in go-and-stop traffic.
0-100-0 in an Ariel Atom [Autocar]
The UK s Ariel Atom: An Open Car for the Open Road [internal]