So.....I purchased a US HomeLink module on eBay for my MS 90D which never had HomeLink at all (no module installed). I took it to the service center and convinced them to install it, which they did. They then had to call Tesla head office in Australia and get them to re-code the firmware to support the HomeLink module. A few days afterwards I got a firmware update message and hey presto....HomeLink appeared on my MCU. So far so good.
BUT......
I think I have made a error in choosing the module version. I should have purchased the EU version which supports 433MHz.
Our garage door opener is a GDO-9V2 Enduro which uses 433MHz.
Looking at the Merlin E8003 uses 433MHz which is not going to work with my US home link module in the Tesla.
I'll have to look online (eBay or Amazon) for the US equivalent of the E8003.
So a word of caution for those retrofitting HomeLink modules......check you get the right frequency version (US or EU).
Fantastic that you were able to convince tesla to activate that. Bad luck about the frequency issue. You should be able to buy any brand of reciever on the homelink list at the correct frequency and wire it into your door. Just watch the power voltage and power frequency when powering the reciever, US voltage is different than ours.