man, I have no idea. I doubt it's a cable-related data rate issue as, from what little I've read, the slow part of an ecu-cable-laptop OR ecu-elm327 bluetooth-smartphone system, is the ECU. There are several revisions of Tactrix so, you have to make sure you get the right one for what you're doing. tactrix is also $$$, vag-com $
Reading your ecu should be no problem but,honestly, you are probably in a unique position and will have to piece together anything you're doing in the way of tuning/re-flashing. Just gathering info here and there cause, I doubt too many people have gone down the path you've chosen. The turbo cars just have more to offer, in the way of tuning, than a '99 NA car and that is where the most knowledge/experience lies.