Surely you must be able to fit a Brose remote/display to a Specialized? Is it like the shimano where it is hardwired back to the motor?[/QUOTE
I would say a very probable yes to that as it is a brose motor and it is a plug connection at the motor end. As long as the hole in the frame is big enough to fit the plug through.
To put the 2018 Eco, Trail, Turbo, Walk mode remote on my 2017 Levo I had to drill a hole in the frame and also cut and re-solder the cable. After that it was a simple push the plug into the connection on the motor.