the custom ones actually look really nice. the one i got for my Audi Q5 looks very OEM (RSNAV). In my case it doesn't actually replace the radio or anything - it's basically just replacing the screen with an android tablet, then piping the sound through the existing Aux sound output. Quite clever the way they did it actually as it lets me keep my existing Audi interface and control systems.
It looks like 4x4shop has a nice retrofit option for 2012 highlander including an option for carplay:
https://4x4shop.ca/product/2008-2013...imedia-system/