[oldskool73]

I have a Chinese Android system, on my second one now, my last one was a few years old and the new one's much faster.

As you already have an aftermarket kit fitted, hopefully whoever did the installation last time already wired in a standard DIN plug, in which case it should be plug and play. Might just be a couple of extra/optional wires you need to attach (e.g for reverse camera if you have one, illumination etc).

Depending on the unit you bought you might need to get a bit creative with a dremel on the facia surround (the 'black plastic trim piece of the car that surrounds the radio' you describe above, which should just pull straight out), the Chinese units tend to be a few mm larger that 'standard' double din, annoyingly, so getting them 'flush' takes a bit of fiddling.