When upgrading my MT4.18 to brushless I needed a way to mount the servo once I gutted the stock ESC/Rx combo.I got the idea from this one: https://www.thingiverse.com/thing:3235778 but it was designed for the stock servo and I wanted to upgrade to a Savox. This one I designed will fit the stock servo, or a Savox SH-0257mg or SH-0262mg, and is a bit more robust than the original.
UPDATE: I added a Kimbrough #112 Servo Saver to my SH-0257mg and I needed more modification to make room for it. I either had to cut a hole in the floor or raise the servo, so I raised the servo 3mm and back 4mm. The Kimbrough version is now available as well.