The Spec 2 package is all about performance upgrades. Buyers can opt for either the standard V6 or the optional 2.3-liter EcoBoost and 5.0-liter V8. The latter is clearly the choice for enthusiasts, now with up to 725 horsepower on tap thanks to an added supercharger. Other performance add-ons include adjustable dampers and sway bars, lowering springs, RTR exclusive exhaust system by Magnaflow, RTR custom tuning, and a cold air intake system. Official pricing for the upgrades hasn't been announced just yet, but Ford did say the 2015 Mustang RTR will be available beginning this January at select dealers worldwide.