You can search the archives at gnttype for the full story. Tom Chou is a powertrain engineer at ac delco who does ecm calibrations for a living. He got interested in TR's and started doing chips for a friend (Heath Elmer who's car was in an early GMHTP), and this evolved into the Thrasher chips which he started selling. An unamed TR vendor then threatened to go to ac delco and raise a fuss, and to sue Tom personally, because he had some kind of "unfair advantage" over other TR chipmakers. Since merely responding to a lawsuit, no matter how frivolous, would have been a tremendous financial burden on Tom, he decided to walk away. He gave his latest chip images to several of his beta testers and told them that they were free to distribute them basically at cost if they wanted to, so they are still available for about $25 which barely covers the cost of chip, carrier, time, and postage, from people like Scott Simpson and others. I was a beta tester for his red-stripe chip, which he never really finished, and he never got started on a chip for 50's since those were either just out or hadn't come out yet when he stopped, but his stock injector and blue top chips are very very good. He was also working with Dave Buckshaw on stuff for the supercharged 3800's, and Dave is carrying on the Thrasher name with those products but has nothing to do with TR's.
I was just learning chipmaking for myself when Tom got into TR's, and we had many very interesting email exchanges and a few phone conversations, where I think we both learned a lot, and I think the TR world is worse off for his absence.
