First of all its is way cheaper to buy a race car than to ever build one. If you have a nice safe street car take that to do a few HPDE's. Then you can decide what you want to do with the car or what class you want to race. IMO I would have a hard time buying or building a Spec Focus because there is noone running the class here in the mid-atlantic region. I have a 96 Integra RS that I know will never be a full blown race car but thats cool with me. Racing is a black hole in your wallet if you want to be competitive.

Here is a little food for thought for those who want to go "racing"

Building a car (Integra RS for HC H4)
Car: 3000
Suspension: 2000+ (shocks, springs, bushing, sway bars)
Wheels and tires: 1000 per set
Engine: 2000-4000 (mild-full prep)
Trans: 1500-3000 (rebuild with new diff and final drive installed)
Saftey: 3000-5000 (Seat, cage, steering wheel, fire suppresion, kil switch)

So on the low side thats $12500 to build the car plus a shit ton of your time. Now add your personal safety gear that will run you $1000-$2000 more.

Ryan Jenkins .RJ on Honda-Tech just sold his winning and well sorted car with all of this listed above for $9000. I am going to have that in my car by next year and it still wont be a "Race Car"

Also like Derek said Spec E30 is looking like a cool class too. It is way more budget oriented than any of the HC classes, well not H5. I think those cars can be bought or built from like 7000-10000. DRFTwizard and is father are running spec e30's and he has done quite well.