and for anyone that might argue that it isn't true, i'll give you this: depending on your dyno curve, you theoretically COULD lose a little top end, because of your power falling off at high rpms. but since gears raise your RPMs at any given speed in a given gear, and since most engines produce more power in higher RPMs, you'll be making more power at that speed, and will be able to overcome wind resistance just a touch better. i'm not saying you'll see a huge difference or anything, my point of this is basically to point out that you won't really lose real-world top speed with a gear change, unless you can top out in your highest gear at red line already. at over 500hp, i still can't top out in 5th gear, so if traction wasn't such an issue, i'd go lower too. i shift at 6300rpm, and according to the gear calculator, at 6300rpm in 5th gear with my 3.73's, i'd be going over 190mph. i wish. wind resistance stops me before i hit that mark.