I did just that and went with 2 700X28 Michelin Dynamics I took my bike for a short ride and the bike seemed to roll faster and required a bit less effort to maintain speeds. With the different tires I was able to bump up my tire pressures from 80 to 100, so that helps as well as the slightly narrower tire. I also went with the power grip pedals. It's still too early to really tell, bu my bike does feel more efficient.