I would like to know what power adapter and serial cable you got too. I've been dealing with the same issues as well. Mine started out around 20 mph off, its within 3-5 mph now, but it still sucks that its not right. Once I got all the tuning the way I wanted it, and drove it for a few days, it really started running good. WOT shifting from 1st to 2nd chirps the tires . It's been a few months now, and it seems to be getting a bit sluggish from a dig. Not sure if thats because its 110 degrees in H-town, but I'm ready for a custom program, and some updates.

 

That is what they did for me to fix my problem with the gears. The next update is not out yet. I got one of the first ones so it doesn't have the knock reading in the live diagnostic area. It's something that I need. I could send it in now and get it but I decided to wait until the new update to see what they added or fixed.

bigj all you need is a standard 9pin serial cable. I just got an adjustable/univerasal power supply from walmart that has different connectors and can select the voltage that you need.
Lar