The idea behind the trick is to keep you from having to cock the motor in such a tight fitting area. The transaxle will just tilt down for you to mount the motor then tilt it back up into place. It makes for an easy install unless you actually have lots of room. With my 9" GE there is but an 1/8 inch gap between the body and end of the motor. Tilting the transaxle allows me to slip in the motor real easy with out binding or catching when the motor is at such a steep angle if I had not angled the transaxle down. By angling the transaxle you actually make a hard job easy. Removing the transaxle completely is more trouble than its worth. You'd need to remove the axles first. Not something to do under the car.
It really does not take much movement of the transaxle to get the job done. You will want two floor jacks but a jack stand for the trans will do in a pinch.