I drove 5 speed 2.7's from my first Tacoma in 95 until I wrecked my 00 Runner in 02, I never felt the need for a 6th gear. The 3rz powerband works just fine with 5 gears to shift through. Even on the new Tacoma the 4 still gets a 5speed, only the six has the 6 speed. I don't think it would accomplish much more than making you shift constantly to be near your power.