This is a variation of the Porsche 987/997 AliExpress Stereo Mounting Rail Spacers by searocko on thingiverse. These are used to mount an aftermarket radio from Aliexpress, specifically from the seller Heregoes, into a Porsche 987 Cayman / Boxster or into a 997-generation Porsche 911.

His original design didn't work well on my car as the head unit would stay very loose and move. I improved the design by making the brackets 2.5 mm taller to wedge the radio more firmly into position. Doesn't sound like much, but considering it's one bracket per side that amounts to a total of 5 mm more bracket. In order to still make the radio slide easily into the rails holding it I added a 1.7° gradient to the top surface. So, besides being taller the brackets are now wedge-shaped. 

The lower part attaches toward the rear of the radio so it can still be easily pushed into the rails but the added thickness on the front will generate more friction and hold the head unit in place much better. It might require a bit more force to push the head unit in all the way but it won't move about afterward.

Depending on your car searocko's original might work better for you and mine might be too thick. On my car however, the rails were quite wide requiring me to produce this version.

Since the part is wedge shaped print it on its side to avoid stair stepping on the top surface (like my first attempt). Use a heat-resistant filament since temperatures inside the car can get hot enough to soften PLA. I used ABS with the standard settings on my P1S.

The first picture shows (from bottom to top):

• The original bracket that came with the radio
• searocko's original version
• My wedge-shaped version version printed on the side
• My wedge-shaped version printed normally