Doesn't having it remapped remove the behaviour you are talking about though? My impression was that until it is remapped the ecu is a law unto itself, but once it's done it stays in "performance mode" all the time. Presumably this would mean that remapped cars can be put on the dyno and give a reliable figure with a single run.
Now had an answer on another thread from Abby, and it seems that the Uprev basically deletes the ECUs ability to switch to the default maps (IE safe maps should heavy knock be encountered) which kind of worries me, it basically sticks to the more aggressive fuelling and timing maps to achieve the boost in performance,
I would very much like to get hold of the software and see for myself just what parameters are actually available to modify/edit in the ECU.
go get the osiris tuner software here http://www.uprev.com/products.php