The reason for removing the spacer is clearance - the switch needs more room and the spacer interferes. The rear of the engine needs to be supported, though it'll be close to balanced on the front one. A jack makes it easier to keep the engine bolt from binding when withdrawing and replacing.
Wanted: Dead, smashed, crashed or trashed gauges
BMW GAUGE REPAIRS - TACH*SPEEDO*CLOCK*VOLT METER *PODs & LIGHT BOARD*