I don't really understand why so many people get so worked up about the Mustang possibly being underpowered when compared to the upcoming Camaro. The selling point for "pony cars" has always been price. The Mustang will always provide excellent bang for the buck, Camaros have always been more expensive.
Any gearhead that cares about power would rather spend $25k on a Mustang and put the extra $5-10k, that would have been spent on a Camaro, back in to their Mustang. My buddy has an 06 GT that is pushing 450hp at the wheels, the total price for his car after add-ons is standing at $33k.