to remove the drive shaft diff flanges you need to remove the rear diff cover (flanges held in place by circlips internaly) and this requires the lowering of the diff. TBH its dead easy to drop the diff on the floor mate...imo its easier on the floor than on a 2 post ramp cos when you send the car up in the air, the lower arms drop down and get in the way of a couple of the diff mounting bolts. Ive changed a couple of mine on the deck and found it quicker than when i changed them at work