Popular article website, "Winding Road," gave a great honest review of the new 2010 Roush 540RH. Their chief editor(Seyth Miersma) basically says that both cars are both powered with a similar amount of horsepower, 540hp for both. What it comes down to is the handling! Seyth says the 540RH "does a much better job at containing vertical movement. One is much better able to put down the massive power with confidence and authority, with the stiffer, better-rotating Roush setup." Also better than the Shelby GT500 was the exhaust tone, Winding Road claims the Roush 540RH is extrodinary louder then the GT500. For more information check out Winding Road's article on the topic. Here are some cool pictures of the 2010 Roush 540RH Mustang.