Lots of extra horsepower, and with Ford's blessing.
Soon enough, there will be no shortage of performance parts for the 2015 Ford Mustang GT, but as you probably could have guessed, Roush is bringing out one of the first really comprehensive power kits, following the body mods it revealed back in September. Full details haven't been released yet, but we're told that the kit will produce in excess of 600 horsepower, and will cost about $8,000. It will be available through various channels, but you can also just have it installed by the dealer.
When it is installed by the dealer, it will also come with a warranty, never a bad thing for what is technically an aftermarket part.