I printed Nonnef's TARDIS Transformer twice. For the second round I revised a few parts.

Be warned!! I printed at 75% scale and designed my revised parts at that scale! If you are printing the TARDIS full size you will have to scale up to compensate!

The "new inner back brace" has some extra bulk that fills in the loose connection to the sliding upper hips.

The chest pieces and torso back have an angle carved out to accommodate the transformation. I had to dremel out over a millimeter of plastic from the original design before the panel would sit flush in TARDIS mode. You may still need to file a little bit.

The original windows don't survive scaling down. I rebuilt them with thicker panes.

The head is an alternate character, Vector Prime. I was disappointed that I couldn't find Nonnef's VP head, so I made my own in Blender then did some touch-up in TinkerCAD. The screw holes are cut out of the original Soundwave head.

There is also a Sonic Screwdriver which will slot into the hand. The top extends and is held by friction.

There is also a Sonic Screwdriver Cannon and Missile. At the larger scale it could use more detailing, but I'm not going to do any more with that. A "Doctor gun" seems kind of wrong. And anyway I don't care for how it looks with a shoulder cannon, so I'm dropping this as-is.

The Sonic Devices were roughly based on my 10th Doctor's sonic screwdriver pen.