Well... If you have a more efficient (you're putting more power to the pedals) cadence, then your cadence should increase, generaly it's kinda hard to measure these things accurately... it's a crapshoot. However, anything that will cut down on your coefficient of drag will increase your speed when using the same amount of power, so any aero mod that works is generally a good idea. If you want I believe you can actually figure out how much energy it takes to move your bike, and play around with different *Cd's/RR's to see how to minimize the force expended. But you might have to measure the RR of your tires yourself, which may be beyond most people, myself included. Not really sure about that...

*coefficient of drag/rolling resistence