Hi KAA and Adrian,
First I want to thank you for your responses.
I think I wasn't explicit enough around what needs to be retained from the stock HU.
On my Toyota Camry (2015-2017 model) there are some features, only customisable from the head unit, which allow me to adjust some speciific car settings. Below are a few examples :
- Door lock settings : Auto lock by speed / Auto lock by shift from P / Auto unlock by shift to P / Auto unlock by driver door etc..
- Lights settings : Headlights on sensitivity (gradually variable) / Interior lights off timer
- Fuel consumption
I emailed 4 well known in-car stereo companies in Brisbane, only one of them responded. They pretty much said they were not aware of those sort of car settings being only available through the HU and unfortunately they couldn't help out.
I have seen an article from Crutchfield (US), stating those features could be retained using iDatalink receiver + Maestro RR but not sure where to go from there in regards to which HU would be able to display those features...