[mfanatic325]

You are right in that a car that's tuned "live" with dyno pulls and ECU tweaking done on the spot is the absolute best way to tune any given car. However, this takes a lot of time and know-how, so these mail-order tunes are based off of dynoed cars they've previously tested, and what you get through the mail is a best approximation in terms of performance AND longevity.
Of course, I'm speaking out of plain logic. It only makes sense that these tuning companies give you the best possible tune WITHOUT any adverse effects to any customer's car(s). Which means that even though they may have based the mail-order tune off of a specific car, they would de-tune it for all other cars that aren't tuned "live" and in person.

As for the ECU being smart, and its ability to adapt, I can't say 100% for certain on any given tune, but I think it has at least a tiny bit of credibility. When I first got my "mail-order" tune with Active Autowerk, either it was the fact that I did not want to overhype it, and was very scrutinizing when feeling for gains through the butt dyno, orrr it was the fact that my ECU hadn't quite adapted yet; and therefore I hadn't felt anything dramatically different. However, after resetting the ECU (by disconnecting the battery) and resetting the throttle adaptation (via the key trick), along with running the car at a track day, I began to feel a much more noticeable difference. Then after the track day when I was certain that the ECU had had plenty of time to adapt itself, I went on to do an "after" dyno so that I could compare with my baseline "before" dyno. The dyno showed a significant amount of change from stock, primarily with the torque curve falling later in the rev band and also less dramatically; which yielded higher peak hp.