What 'racing' do you want to do? Every different discipline has very different requirements, of both the car, and of your skill. What makes a good drag car will make a bad circuit car, what makes a good circuit car will make a bad sprint car, what makes a good sprint car makes a bad drag car etc.
How much experience do you have? Excuse me if I sound blunt - but if you're asking this question, I shall assume none!
By far the best thing to do is to start off with what you have.
Learn how to race first. Decide whether you like it. Then learn the car as it is. Once you know what you're doing, that you enjoy it, and know the car, you will then be in a better position to understand what aspect of the car you feel is holding you back from progressing further.
Don't go throwing money at something until you know what it is you need to spend money on.
If you're wanting to get involved with the OSFDC next year, then come along in your car as it is, and have a chat with some of the regulars. The likes of Steve Jennerway, Brett Wright, Chris Todd, Robert White and others have helped me greatly this year in getting to know how to drag race, and without their help and advice, I'd have not made the improvements to myself that I've made this year during my first year of the OSFDC - this interaction, and these improvements have made a better impact to my times this year than every penny I've spent on the car - by far the best value-for-money approach.
I now know where my limitations are with my car, and what I can do to improve it - but I still have more I can do to improve myself - this is something that will continue for many years!