If you keep an eye out, you can sometimes find really good deals on Radical's. His runs really strong and the suspension is set up well, it's fast, so it's a good deal. If you buy new you'll end up spending an extra $40k. I got my 1500 from PVM Racing in Atlanta with only three track days on it and a zero hour engine since the previous one had blown
Sometimes they have them pop up on their website under cars for sale. Very rarely you'll even see them on ebay but those are the ones you usually have to watch out for. I'd only buy one from someone who will either drive you in it for a few hot laps, or less often, let you drive it.