I've broken a motor mount before, so I'll tell you, they can help. If you have a high torque or hp application, they can add just a bit of security. I had a kit on the engine that broke the mount, and it kept the engine under the hood; barely. The intake manifold had literally ginsued itself on the edge of a piece of sheet metal that belonged to the underhood structure; I couldn't believe it! The hood really didn't dent or buckle, but it wasn't quite normal. It was a high RPM launch off the line while drag racing, and that just did the trick. The other thing is that it effectively reduces high frequency engine harmonics. The vibration that stresses parts can be transfered through the damper, lightening the load on a great many things. If nothing else, they look pretty cool. How much did these list for?

John