License? The Zietronix is an addition you can add for increased functionality. The Dashdaq "alone" reads signals from the OBD2 port. IAT's, ECT's, Boost, STFR, LTFR, speed, throttle position, more, more and more. The Zietronix is usually added for the wideband AFR capability. You can get much faster sample rates of some of the same info you receive from the Dashdaq through the Zietronix. Start with the Dashdaq and if needed or wanted, the Zietronix can be added at a later date. You will learn quickly what is normal watching the information available with the Dashdaq. I can't imagine not having mine.

Les