I have 4.10 gears in my 2007 GT and I find them to be just fine for daily driving. I can pull out easily at 1,000 rpm in 4th gear with no issues. This makes driving around town much easier. I think it runs around 2,300 rpm at 70 mph and I get 23 mpg on the highway. IMO, if you are going to the cost and trouble just get 4.10 gears because going with anything less doesn't deliver all that much of a performance gain from 3.31 gears for a mostly stock NA engine. Mine has a Steeda tune and intake. The 4.10 gears are a perfect compromise between performance and drivability.