The DynoJet box you speak of has a greater tuning area. What I should say is the Yosh box has 4 knobs and changes the prom value. The DynoJet box installs on your bike and will let you change the settings in real time. You have the ability to change in 500 rpm increments from 0 - 14k. You create a "map" using this table and then load that to the dj box from a laptop. This does not change the bike prom.
The box comes with a standard map, I'm sure what they are talking about is a map created by them for their exhaust system. This may or may not work for you.
The box also wil alter throttle position and manifold pressure. The new DJ-2 will also adjust timing.
This is not a "first timer" box, I would suggest that any tuning is done on a dyno with an exhaust gas analyzer while using the DJ box.
