Don't over think it. Once the race starts it will come down to the rider, lungs and legs regardless of what your sitting on. The bike, assuming its tuned up and functioning correctly, won't hold you back much at all. If you want to do something to help you feel faster on your current bike look at some good lightweight tires and or wheels if you can swing that as they will have the biggest impact. Most local races will have different classes you can sign up for Expert, Beginner, Sport etc.. so you can potentially race with others of same ability.