I am using the T/Max but it is easy to understand why it even works BETTER than a High $$ Dyno tune. An inertia Dyno tune is nothing more than a WOT blast for a few seconds. They are tuning at low map pressures only and they do not take into account any "cruise" A/F ratio's because they can't (if using an inertia dyno).
On the other hand, you are already paying rent on the best dyno available which are Public Roads. Every possible type of load there is will be matched to the perfect A/F ratio by the firmware in the T/max ECM.
If you have the Wide Band setup with auto tune, I can not see any advantage to using a Dyno.
If your using a narrow band set-up, you will have to dyno tune.
also the tmax is a direct replacment to your factory ecm where your powercommander is a piggy back.
Cort don't think about it. DO IT. I love mine. One thing he didn't mention was a three year warranty. Zippers tech support is great as well. You can data log on the unit, email it to zippers, then they will call you to talk about your issues. This is a hands down must have if you are planning on doing any motor work. It's even boost and spray compatible.....hint hint. That is a great price. All you besides the unit is a set of head pipes with 18mm o2 sensors. If you need a set let me know