I have 3 friends running intercoolers made by a company called HYBRID. They are bar & Plate, and about 24x10x3. They all are making good numbers with them on their EVO's, and they got them off ebay for right around 300. I'd keep an eye out for them if you can find one. They are cheap, and apparently they are working just great. I'll keep an eye out too.
Also as a cheap alternative, I have heard a lot of good things about the stock EVO intercooler. Someone else please chime in, but I was researching it because my friend had bought one off another one of my friends. I kinda thought it wasn't the smartest thing at first until I started reading. And supposidely those stockers are supposed to perform pretty good. Anyone else hear this??
edit... I just looked on ebay and couldn't find any of the HYBRID companies cores for sale, but I did find this KIT with a picture of HYBRID's cores just to give you an idea of what their cores look like.
http://cgi.ebay.com/ebaymotors/ws/eB...ayphotohosting