I didn't get an invoice... The tech actually worked on our KL until after much of the place had shut down, since it was all warranty, I just left... I'm sure it's documented though so I will get it.
I think the issue is how the 3.2L's power comes on... I took the dyno chart from the AFE website, but you can see that it almost behaves like an old 2-stroke that hits a powerband. There are pretty drastic changes in the power it generates from 2000 RPM through 2400, and it makes little to no power at all at idle. Since the ZF9 has so many gears it is doing it's best to work with what it has but adding even the slightest of wind drags would force the power requirement up and this means dropping gears.
Now, the question is if a turbo or supercharger would help more (if we pretend one existed). A small quick turbo may be what the Dr. ordered, but IMO a supercharger and for low-end is what the KL desperately needs to make the most of that ZF9.
I know lots of people won't agree with me, but I know what you are talking about the drastic power increases from 2000rpm to 2400rpm, however I think that is a limitation on the tuning. Something is holding back the power below 2400rpm on these vehicles.