Originally Posted by
andrewclaus
I'll go against the grain here and suggest higher pressure, narrower tires will make more of a difference in the way that bike feels than different pedals will.
I agree. Clipless pedals are wonderful things, but they don't make you much faster.
I've heard that you can usually get away with about 1.5x the max pressure a tire is rated for, but if you're running 28s, well, I used to run 28s at 110 psi, it can be done, but they're not really meant for that. I'd check to see if your rims will accommodate narrower tires. Those, also, can easily be moved to another road bike some day, if you haven't worn them out yet.
Also, upgrading the engine is free.