The 5-Star tune alone will get you to around that number, assuming you're using 93 octane fuel and depending on you ambient conditions. The thing with just about any vehicle that comes from the factory with forced induction, is that their stock tuning is very generic so that the vehicle can use just about any grade of gasoline in just about any climate. A custom tune increases boost pressure and adjusts other key parameters of your SHO's factory ECU programming to make all that extra power. All you have to to is stick with the prescribed fuel octane that you're custom tuned for.