The 2009 BMW M3 is available as a sedan, coupe or retractable-hardtop convertible. Based on the compact 3 Series, the high-performance M3 comes in a single trim level. Standard features include 18-inch alloy wheels with performance tires, xenon headlamps, cruise control, automatic climate control, leather upholstery, heated power-adjustable sport seats with driver memory, split-folding rear seats and a 10-speaker audio system with a CD player and an auxiliary audio jack. The coupe features a carbon-fiber roof, and all M3s receive revised exterior styling, an exclusive sport-tuned suspension, more powerful brakes and a limited-slip rear differential.The optional premium package adds power-folding mirrors, BMW Assist and enhanced interior trim. The technology package tacks on M Drive (which allows the driver to adjust throttle response and steering feel), a voice-activated navigation system, iDrive, keyless ignition and entry and electronically controlled dampers. À la carte options include 19-inch alloy wheels, a sunroof (sedan only), heated front seats, rear park assist and a number of audio options, including an upgraded sound system, HD radio, satellite radio and an iPod adapter.