I am in the process of doing this too. I want to install the car joying 10.1 android system. I have something similar in my cayenne and it's awesome.
I have a 99 boxster as well. I moved the AC controls to the bottom most slot in the console. I added a storage bin in the top slot and the trim around it. The hardest part is getting the cables there. I used a wire hanger to do the job, took me about 1hr to route the AC cables.
In the center console I also have several switches like the lock switch, convertible top, and the rear defroster. These switches will certainly be blocked with a 10.1 inch screen. So I bought a 4 switch batwing and it goes below the AC controls. The challenge here was the cables were too short, so I am making wire extensions with crimps.
That leaves the entire top double din empty for me to install the 10.1 inch stereo.
https://www.carjoying.com/head-unit/s-v/vw-head-units/joying-in-dash-android-auto-audio-dab-radio-10-1-touch-screen-panel-hd-bluetooth-car-gps-navigation-system-volkswagen-golf-polo-jetta-amarok-passat-scirocco-touran-eos-beetle-skoda-octivia-rapid.html