I am exactly the same way, i want modification but quality should be OEM, i dont care about warranty tough.
Waisay for android head unit what you can do it buy a middle harness from AliExpress which has the same connector as your stock wiring harness then and cut or match any wires in that so your stock cars wiring harness stays the same untouched as well as your LCD connector.
I have a JDM alto and its speaker connectors are like alien shape for stock speakers, still i have managed to install new components with tweeters without any wire cutting.