guys how much to upgrade the city V spec HU to the one with navigator and reverse camera?

Looking for a V spec city for my wife, the dilemma is the GPS part

memang can add GPS into the pre-existing V spec HU??

My wife not keen to use the mirror-ing function.. as phone is not that reliable, eg no more data, no gps signal, phone no battery etc, wire rosak.. etc

Not too keen to spend another rm3k+ for the upgraded ori honda multimedia system+navigator

so, any 3rd party can do it all? mirror+gps+bluetooth+reverse camera?
another option.. is to get a standalone gps..
any idea?

anyone install leather seat?? for new car the car agent quote me 2.5kgst for half leather
and 3k for full leather?

they say if install incorrectly it will make the airbag malfunction?
correct me if i m wrong.