RX8Club.com - Review : Knight Sports Final Drive 4.777 on 4AT...

Quote:

Originally Posted by mdw1000 (Post 3275915)

Your stock gear is a 4.44, so this is about an 8% lowering of your rear gear. Basically has the effect of making every gear lower. You'll gain some acceleration at the expense of top speed in each gear and a slight loss in fuel economy.

Another alternative to 4.777 final drive would be downgrading your wheel to 17" or have a slimmer tire.

change to:
235/40R18 = FD 4.540
245/35R18 = FD 4.661 ( the sidewall might be too thin and affect the drive comfort)

OR downgrade to 17" wheel which will save you some weight, cheaper tire and have better fuel economy but still having shorter final gear ratio. BUT...maybe an uglier looking ride.
235/45R17 = FD 4.554
255/35R17 = FD 4.800