Seriously, you've got what- a 3200# car? 537 horse? Unless you're racing every weekend, you won't "need" 4.10s or 4.56s to have fun on the street (ratios aren't HP dependent; it's more a function of how much torque you make at your average operating RPM. Think about it- Top Fuelers run 2.90 gears...) and keep it livable. Believe me, you don't want to deal with driving that thing at your rated 6K all day long.