About motor mounts. The assembly of the engine on the mounts will have a resonant frequency. That frequency is dependent on the weight of the engine(divided by 4), the design of the mounts, and the stiffness of the mount (durometer). When the engine runs at the same RPM/60 as the resonant frequency (Hz), it will vibrate like crazy. So, you need to select a durometer that will cause the resonant frequency to not be in the operating range of the engine.
The durometer should be stamped on you current mounts. It should be a number between 45 and 75. Since it also depends on mount design, if you buy the same mount, you can buy one of the same durometer. But if you buy a different mount, the required durometer might change and you will need to check with the manufacturer of that mount for proper selection.
As an example, here is the product sheet for a popular type of mount(but different from what you have), with the charts used for selection: