I have obd1 on my 350 chevy. I was able to connect up for under $100, less if you like to collect parts and solder. Software is free. My ECU has a flash programmable eprom. I have one tune for milage and one for power. I can data log and read trouble codes. There's a cool virtual gauge program available too.

All it took was a few nights of digging through the internet. google seems to have really gone to ***** recently. They changed their engine a few months ago, now it real easy to find places to buy stuff but it's real hard to find places with info on how to make your own. they sold out. I use dogpile and yahoo when google lets me down.