I don't know to what extent you really plan to race. In this case everybody is a little off the mark- not because they are wrong but because they are not thinking out of the box. The thing that you can do, that will save you thousands, is buy something turn key. The more high dollar the set up is- the steeper the discount. If you are careful you can get a 30k+ car for less than $10,000. I know a lot of the stangnet guys will hem and ha over what I am proposing but it's the truth. Thats what I do. I found my current car on EBAY. It was listed locally so I went out to see it, brought cash.....the auction ended by the time I left his house. He had well over 20k sunk (maybe even approaching 25K) into it and I drove it home for 7K.
Anyway, if you are on a budget, spending more up front is usually the best way to go. Sometimes it's worth buying a whole car just for parts.