Originally Posted by t walgamuth

If you want more acceleration you need a higher number in the gear ratio. Your car is a 300d turbo? If you want more acceleration and your car currently has a 307 diff you would want perhaps a 346. You would gain acceleration but lose economy.

If you wanted better economy you would want to go the other way, perhaps to the 247 diff.

The only way to have both is to get more gears to work with in your tranny.