The mid-level Challenger is powered by a 5.7 L (345 cu in) Hemi V8 coupled to a 5-speed automatic transmission or a Tremec TR-6060 6-speed manual transmission. On cars equipped with the automatic transmission, the engine features the Multi-Displacement System and produces 372 brake horsepower (277 kW) (SAE) and 398 lb·ft (540 N·m) torque. With the 6-speed manual transmission, the Multi-Displacement System option is deleted and the engine produces 376 brake horsepower (280 kW) (SAE) and 404 lb·ft (548 N·m) torque. Another feature is the Intelligent Deceleration Fuel Shut-Off (iDFSO) available with the manual and the automatic models, the first to combine both Multi-Displacement system and fuel shut-off. The final drive ratio is 3.06:1 on cars with the automatic transmission, 3.73:1 on cars with the 6-speed manual and 18-inch (460 mm) wheels or 3.92:1 with the 6-speed manual and optional 20-inch (510 mm) wheels. Also available on R/T is the "Track Pak" option group, which includes the Tremec manual transmission, a limited slip differential and self-leveling rear shock absorbers. During the end of the 2010 model year, Dodge released the special edition "Mopar '10" Challenger R/T. The Mopar '10 featured a myriad of Mopar aftermarket upgrades straight from the factory including a Mopar cold air intake, hurst pistol grip shifter, custom Katzkin leather interiors and R/T Classic wheels that are painted black as opposed to the standard chrome. All Mopar '10s had metallic black paint to go along with a choice of three different colors for exterior striping (blue,red, or silver)