You may have noticed the big announcement that ROUSH Performance made last week: that our all-new 2015 ROUSH Stage 3 Mustang is producing 670 horsepower and 545 lb-ft of torque. That’s an incredible 235 horsepower and 145 lb-ft over a stock 2015 Ford Mustang 5.0L. With 134 horsepower per liter, the 2015 ROUSH Stage 3 Mustang overshoots the competition with the most horsepower per liter when compared to Dodge’s most powerful offering in the segment (114 horsepower per liter) and the 92 horsepower per liter rating of another well-known supercharged 6.2L GM engine in the segment. Power is important, but high horsepower numbers don’t mean nearly as much if you’re trying to move a ton of weight. The RS3 is again at the top of the ranks with the lowest weight per horsepower of the competition (approximately 5.70lbs per horsepower) compared to an estimated 6.32lb/hp* and 7.10lb/hp respectively. All 670 ROUSH horsepower are created as a direct result of the powerful pairing of Ford’s 5.0L V8 engine with ROUSH Performance’s dynamic new 2015 2.3L TVS supercharger and the calibration of a brilliant team of ROUSH engineers. The new ROUSH Mustang’s generous power ratings impeccably compliment the RS3’s list of standard and optional features, including the ROUSH Quad-Tip exhaust (with optional ROUSH Active Exhaust System), standard single-adjustable coilover suspension system (or optional competition-tuned 3-way adjustable system), and the fierce new “R7” aerobody. The 2015 ROUSH Stage 3 Mustang is not just a car – it’s an experience. The RS3 truly bridges the gap between road car and race car, putting drivers behind the wheel of the ultimate uninhibited muscle car. Jack Roush’s vision shines through the 2015 ROUSH Stage 3 Mustang’s perfect combination of 670 horsepower with meticulous handling and braking capabilities, providing the driver access to the robust attitude and performance of a racecar, while maintaining a comfortable and uniquely ROUSH driving experience. Source: Roush