Lowering engine mouinting point

[vex]

The rubber is to reduce the vibration transmitted through the chasis. In effect it isolates the engine from the car allowing the engine to operate independent of vibrations on the car.

If lowering the engine is worthwhile you can easily get another drive shaft made and ensure the proper angle between the transmission and differential. The end issue (beyond angle) is how much of the fabrication you're willing to do to ensure proper angles.