since it sounds like you are building out your home shop for the first time have you considered the following:
-space for bandsaw, drillpress, air compressor, 3 phase converter (if needed), tool cart, stock/other storage, workbench
-fresh air supply (cant do any real machining in a garage that is recirculating air (fine chips + coolant mist)
-climate control (got to be reasonably comfy or you wont go in there to do any work)
-noise
-reducing the machine height to get in your garage by taking the z axis motor off
-whether your garage door header is actually a header (if its a gable construction it may not actually have a real header and so options for cutting a removable slot in it go up)
-whether you can make a relief/recess/hole in your ceiling to accommodate a tall z motor if need be
-there are definitely VMC's out there below 99" (with z axis motor installed)