Welcome to the wars.

The answer to the "How much does it cost?" question is always, "How competitive do you want to be?"

A stock engine isn't going to get someone to the front of a competitive ITA field but for someone just starting out, the learning curve will be steep enough that power isn't the biggest concern.

You'll hear this a lot but I'll be the first to say it: If you can find something already built, you will save a LOT of money over building exactly the same car yourself. This is particularly the case right now, with the economy making it a buyers' market for race cars.

There's some people here who can give you guidance on the spring rate question but before you get to that level of detail, do some shopping around and see what you can find on the used market.

K