What do you have on the bike now in terms of wheels (hubs, #spokes, rims), tires, cassette, and chainrings? If you are running wide touring tires (28, 32, 35 mm?) now, you'd benefit from narrower (23, 28 mm) higher-pressure tires. You may want to replace a wide-range cassette (12-34?) with a much narrower one to gain tighter gear spacing. Do you stil want to tour sometimes, or do you want to give up touring capability for fast riding?

My new custom Peter Mooney bike is set up for both touring and fast road rides. I have 2 sets of wheels for it, one with 650x23 tires and a 12-23 cassette, the other with 26"x1.3" tires and a 12-32 cassette. I swap them about once a week. The most noticable difference is having widely-spaced gears vs closely-spaced gears. And the difference in tire width changes the feel of the ride and lets me carry a load with confidence. If you have 700c wheels, you can get both narrow and wide tires to fit the same rims, but may prefer 2 sets of wheels as a matter of convenience.