Quoted from C_Presley:So I was recently gifted two mars units, one up and one down.
I'm sure you've probably figured it out by now, but all you need to do is buy the upstacker bezel and swap it. Think it's like 4 to 5 screws depending on which way you go. I only use down stackers on a handful of games.
This one
https://www.dsvendinginc.com/p-9424-d250064300-marsmei-merchant-media-bezel-kit-clear.aspx
or this one
https://www.dsvendinginc.com/p-2316-d250065014-marsmei-vn2511-bezel-kit.aspx
comes with everything needed.