This is an adapter for a generic "Steering Wheel Button" available from Amazon, Aliexpress, etc. to mount it naturally at the same height as the steering wheel. 

I recommend printing face down, with supports to hold up the base for the remote, and the support arm going to the car plate.

The car base plate attaches with double sided tape. I made the plate 20mm wide, so that it could match with my roll of 20mm-wide 3M Automotive double sided tape, which works well for this application. 

About the fit, the diameter of the inner wall circle is 36.3mm and initially I tried 36mm, but it was too tight, and then 36.5mm  was slightly too big. If your printer's calibration is different then mine you might need to make a similar adjustment to ensure a perfect fit where the remote slides in well, but doesn't fall out on it's own.

I am using it on my first generation Toyota 86 (ZN6) - same as the Subaru BRZ - but you could probably mount it on the wheel of almost any car. I attached the source file from Fusion 360, so if you'd like to modify the file you can do so . Changes I recommend would be to edit the angle of the second sketch to match your angle of the steering wheel surface vs. the attachment surface, or to edit the thickness of the extrusion of the plate where the tape attaches (currently this is 8mm I think, but you can make it more or less to match your own car).