Good question. I posted a longer post on this subject on another forum that I'll repeat below to hopefully answer your question.
The full vent:
It turns out that Club Car does something at the factory to the controllers on the XRT850E?s to prevent speeds higher than what the #3 setting allows. I am told that this is because of the factory lift kit on the cart.
This didn?t stop Club Car from going ahead and selling my controller?s unique #4 speed code to my local dealer so that they could sell it to me, though. The controller accepts the code and does indicate speed mode #4, but thanks to the extra factory tweak, the top speed of the cart remains as it is for setting #3.
It took two 60+ mile round trips to the dealer, multiple calls to Club Car, and many hours of my time before a Club Car regional sales rep finally figured out what the problem was and told my local dealer that the code never should have been sold to me in the first place. They refunded my money, but I still feel like I?ve been screwed. Especially since Club Car assured my local dealer that the code was correct and that it would work before they had me haul the cart back to the dealer the second time.
Venting complete. Thanks!