When you read the bike magazines or surf the web, every company is telling your that their gadget is the one that is going to unleash your inner tour winner. Have you bought a carbon fiber widget hoping to get that little edge? If so that's cool but it comes down to science on what upgrades will actually make you go faster and which ones are just bling.
In an ideal world we wouldn't concern ourselves with cost because we would all be independently wealthy but that's not the case for most of us. Most of the time the things that give you the biggest gain cost the most.
For a road bike the upgrades will fall into the following categories, with overlap sometimes
To get the most out of your road bike you need aerodynamic, lightweight, good stiffness and a comfortable ride. The list below will help with all of these traits.
Carbon Aero Wheels - While the most expensive upgrade, they give you some of the biggest gains as they cut through the air and are usually lighter than most aluminum wheel sets.
Rotor Q-Ring - 4% more power, less muscle fatigue and easier on your knees. Rotor rings are a no brainer for the price.
Tires and Inner Tubes - High quality tires can cut both rolling resistance and rotational weight. Add in light weight inner tubes and you get a difference you can really notice. Good value for the performance.
Power Meter - While a power meter doesn't directly improve performance, they allow you to make your training so much more effective that they can out perform all other upgrades. It's still the strongest rider who goes the fastest and power meters allow you to get faster quicker when combined with smart training.
Bearings - upgrading the bearings in your bottom bracket and hubs to high quality ceramic bearings is another way to get a little edge. The improvement isn't as big as wheels or Rotor Rings but when you have those toys then this is another way you can buy a little speed.
Bike Fitting - Getting a professional bike fitting can do wonders for both comfort and speed. By getting proper structural alignment you will get the most out of your body.
Pedals - Saving some weight from your pedals adds up over the thousands of pedal strokes per ride. As well a streamlined pedal like the Speedplay Zero will reduce aerodynamic drag.
Handlebar - Not so much to save weight but to get you in a more comfortable position. The FSA Compact design which is available in aluminum and carbon just fits the hands better.
Shoes - A light weight carbon road shoe will save energy every pedal stroke. The longer the ride or race the more benefit your will notice.
It's in you to become a better cyclist. Helping you get there is my number one goal. Equipment, riding skills, fitness and nutrition all have to be dialed in to reach your potential.