2010 BMW M3 GTS The M3 GTS had the largest engine put in a 3-series, a 4.4 liter naturally-aspirated V8. The GTS was an order-only, track-focused car. However, you could get it ordered to be modified in order to make it street-legal. Many modifications were made on the exterior, with a carbon-fiber front splitter, an adjustable rear wing, rear splitter, and four exhausts. For the interior, the rear seats were removed to save weight and an FIA-approved roll cage was installed to boost rigidity.