Everyone is right including Flyboy's comment about fuel soaking. But I think a break-away mount is a good idea because it helps absorb energy and cause less damage.

The reason the mounts get fuel soaked is simply because they aren't fuel-proofed properly. Some of them have no fuel proofing at all and others get fuel proofed before the holes are drilled.

Finish the mount completely including all holes. Then drop the mount in a can of clear poly for an hour letting it soak. Shake the can occassionally. Pull it out and stick a wire through one of the holes and let it drip dry. I use a paper towel to soak some of the puddle off at the bottom after it stops dripping because some of the poly pools there.

Anyway, it's simple and it works.

Also, I recommend using stainless steel hardware around the engine. It holds up better. Allen heads are best because you can use a ball-driver to get at it when you don't have a straight shot which is common around the engine. Use a regular allen wrench to tighten down the bolts though. A ball driver can't handle a lot of torque unless you buy expensive hardened drivers.