I don't see any good reasons for running a solid plate mount. This would transmit and unbelievable amount of noise from the motor to the frame and interior of the car. It's bad enough from just a Holley "blue" fuel pump. I have used urethane mounts for 2 years and 18k miles and nothing is broken. It will be very unlikely you would ever get enough traction to break anything unless you run slicks. If you do the first time you get loose in some water will be a real eye opener.
Why would you need solid mounts for this kind of cruize??