I got a HPT serial cable after I went with a friend to Ed Wright's shop in Tulsa to get his 02 Trans Am tuned. Ed took his PCM out of the car, went into a room and closed the door. He came out 10 minutes later, put the PCM back in the car, did 4 WOT dyno pulls and charged him $650. We were there about 1 hour total. I read that tune file after I got HPT and when comparing it to a stock file it is almost criminal what Ed was charging $650 for.