I looked a little on ebay and some of this stuff seems kinda shady

1tarpstech (2) Jul-28-02 12:34:32 PDT 1843512030 S
Complaint : HIS CHIPS DON'T WORK AND HE IS A SCAM ARTIST DON'T BUY HIS STUFF
1tarpstech (2) Jul-28-02 12:26:13 PDT 1843511780 S
Complaint : the chips don't work and they are all the same no mattter the car. Its a scam!!!

What does this chip do exactly? Is it like a poor man's VAFC?