It's a bit of semantics, but there is a difference between the power a motor is capable of delivering and the amount of power it is actually delivering at a given moment. I believe what Kardax meant was that putting a less powerful motor in the sedan won't necessarily improve the range. But certainly driving less aggressively (i.e. requesting less power) will. A limp mode simply limits how quickly you can accelerate and top speed. This is something you could also do with your right foot.
My point was that the range number is obtained by using a specific driving pattern, dictated by the EPA. This is independent of the kind of driving modes you are talking about, though there probably is an optimum regen profile.
This sort of technical discussion is probably more appropriately continued in this thread:
http://www.teslamotorsclub.com/futur...whitestar.html
.