Fanwinking may result in muscle strain.
*SPECULATION ONLY!!!!*
The third warp nacelle, for sake of design ergonomics, was disguised as a standard nacelle. It is in FACT, some sort of new or adapted slipstream or transwarp drive, allowing the ship to move at warp 14, as according to the new warp chart.
*SPECULATION ONLY!!!!*
I dunno. I mean, I'd rather accept my favorite cannonical episode as opposed to what has been said out of series or what have you. I agree with the analogy of car tires tho. By that logic, however, why do you need two at all? I guess for a stable warp field two is necisary. Maybe three creates a field of a diffrent shape?
-M