It was always clear to me that the original MCU in our 2017 MS was not up to the tasks that it was being asked to perform. Very slow, timeouts, freeze ups. After almost all software updates, I could never access the update details. Surfing the web was almost impossible, even with WIFI. One of the most frustrating was the inability to access the owners manual. It just wouldn't load. I wore my thumb's out rebooting. If you noted the past tense in the above comments, it is because we paid the $2500 to install MCU2. It was quite a journey to get the upgrade. I ordered it through my local service center when they notified me that I was eligible for FSD upgrade. I tried to order the new MCU so both updates could be done at the same time but that didn't work as they couldn't get the new MCU. A month or so later, I was notified by automatic email that the new MCU was delivered, in my name, to the service center. Unfortunately, before I could set up an appointment, they called me to inform me that they were diverting my unit to someone else who had a failed unit. I wasn't happy but I understood the reasoning. The unit was reordered at that time. About a month and a half later, I was again notified that the unit had arrived and this time, I forked over $2500 and it was actually installed. Was it worth it? ABSOLUTELY! The difference is astounding. Almost all functions are instantaneous, the graphics are better and I can even surf the web without WIFI! It has really transformed the feel of the whole car. Naturally, I hope that I will be reimbursed all or most of my $2500, Maybe Tesla could offer a discount on future purchases instead of returning the fee. How about free FSD on my CyberTruck reservation?