From what I have seen the 140 is a great match for that plane. I dont know if there was any added weight or if it balanced perfectly. But they do move out. I am sure a 120 would be a good engine as well.

Yes $200 is on spot for that soft mount. Maybe look at a Hayes soft mount but be sure to get a nose ring.

I just think a 110 would be "Ok" for silver, but may force you to have stick it on the poles everytime and leave no room for error.