I just was able to watch these video from Kenny Boxster's thread:
http://986forum.com/forums/diy-project-guides/37615-boxster-motor-mount-tips-pointers.html
I am going to take a few left/right turns on the way home and peek to see if the engine moves side to side, but I don't think it does. After watching his video I think my engine movement might be normal and within the limits of the motor mount. I guess if it was a solid racing mount then instead of deflecting and compressing all that vibration/etc would be transmitted to the body of the car and to me
Then I will put that cover back on, I am afraid I am going to put a sleeve or something back there and get it tangled up... I would not have left the house if I had remembered it was off (it was on when I took my first test drives but I took it back off to verify the belt was running smoothly...)
Steve