While my bike was in getting the new heads, gaskets, etc I asked the Service Manager about this. The download on the older manufactured bikes is not rider controllable. The dealer downloads it and it is active. If you decide you don't like it you have to take it back and have them download the original settings back in. I had him do this on my bike to verify, and he was correct.
It is not by model year, but by maufacture date. I do not know what the cutoff is, but I have a '08 CUSE3 that was manufactured in July '07.
I tested it, and the only noticeble negative is a very slight hesitation when pulling out ONLY after the system shut the rear cylinder down. If the heat management is not kicked in there's no difference. I don't see that I'd ever turn it off so it's not a big deal for me.
I will say this about it, don't expect this to make a major difference. Yes I could notice it. But I'd still reccomend a re-tune if you have one that is running excesively hot. Mine does not. I had to let it sit still and idle for about ten minutes before it got hot enough to cause the system to kick in. And when it did I could notice a slight reduction in heat. So instead of frying my thighs I'd say it went down to flame broiling.
Ride Safe,
J-Carr