Akikiki
A'-Lo-HA ! y'all
any estimate on how much Tesla would charge to upgrade the repeaters?
Its unlikely that Tesla will agree to take on the work for pay to install newer repeaters. They generally don't want to be a party to change the car's factory configuration. That's what they told me when I asked them to activate the FM radio that I installed myself after MCU2 upgrade. They don't want to deal with changed cars in the fleet (so they told me).
That does not mean you can't change them yourself. They are not restricted parts. And you can find on Youtube how to do it. Its recommended that you do not swap them until you have a OTA update pending install. There's a deployment process that occurs with OTA updates, and it can/will assist your car with recognizing the new parts.
And I agree with @watt, pillar cameras won't make a Sentry/Teslacam difference. A couple of people have already swapped those.