5th gear on the FE tranny is the same as the 4th on FC trannys.

There is no real advantage of the RX-8 tranny, and 6th on the FE tranny is taller (.84 vs .71) than the FC, resulting in lower mileage. FE gearbox has 5th as its 1:1. The FE tranny is good for 250 realy base FE HP people that go past this are braking them alot. The FE gearbox is the same as the Miata 6-speed



Compare the FE 164ft-lb to the S4 TII's 183ft-lb and the S5 TII's 196ft-lb. Suddenly an RX-8 gearbox a modified 13BT doesn't seem all that smart...



RX-8 Gear Ratios: 3.76:1, 2.27:1, 1.65:1, 1.19:1, 1.00:1, 0.84:1

Final drive 4.44:1

 

Don't forget how much the 8 weighs. That is a big factor when it comes to the transmission failing.