 Perhaps best known of these Roush-modified vehicles is the Ford Mustang, which in 2016 is available in the "RS" (3.7 liter V6, with body kit, stripes, wheels and interior modifications only), "Stage 1" (standard 5.0 liter V8, with body kit, stripes, wheels and interior modifications only), "Stage 2" (standard 5.0 liter V8, with body kit, stripes, wheels, suspension and interior modifications only), and "Stage 3" (body kit, stripes, wheels, suspension, interior, and exhaust modifications, with the addition of an Eaton-supplied 2.3 liter TVS-2300 "roots-style" supercharger).The addition of the supercharger to the Ford-supplied 5.0 liter engine on the Stage 3 version results in a horsepower output of 670.All Roush factory cars are 50 state street legal.