this question is impossible to answer , matching your bike to your body would be the first step , but in practice you could have the best bike money can buy and do terribly , or the worst bike and do great in your race and all types of combinations in between , there are just too many variable to say !
i personally would start by matching your body to your bike , study your position , seek out pro bike fitters , study the various heights and lengths or each area of the bike , make changes over time , use measurement tool like power meters to visualize the improvements or setbacks you get , its going to take time and practice , thats what pros do , you can get a base line from a bike fitter but over time you might get more flexible or sit in a different position , you have to just start paying attention to how the bike effects your body so you can maximize your efficiency in cadence and reduce fatigue of your muscles .
if you are trying to spend money to gain performance , start with your drive train , reduce as much friction as possible , craft a race day set up of parts that you dont train or ride daily with so they are fresh and clean , get high quality race wax and make sure the chain is perfect .
another thing you can do is recon the terrain so you can adjust your chain rings and cogs so the chain line is strait in the most common gear you will be using , that makes a huge difference up hills if your chain is slanted you will loosing 10s of wats compared to strait !