Hey there, Marty!
I'm finally getting mine replaced next month (April 24, 2023), after 'kicking the can down the road' for almost a year. The loss of 3G is what triggered my desire to upgrade. My 12 year old son wants all the extra games.
I simply requested the estimate for the upgrade via "Service" in the Tesla App. With parts and labor, my invoice is quoted to be $1880. I'm hoping I can still have FM radio and Sirius XM. I think that's the case. Normally for the MCU alone it's $1500, but mine is $1750 and labor pushes it to $1880; which makes sense considering the $250 for the radio and SiriusXM capability quoted for early adopters of the MCU1/MCU2 infotainment upgrade.
Make sure you request the FM radio/SiriusXM if you want it (and if they still have that available). Also, make sure you request they transfer over your navigation favorites and other custom settings. They should automatically do that, but each service center might be a bit different, so it doesn't hurt to ask.
Good luck and Happy Motoring!