Be careful what you wish for. Those firmer mounts will transfer more vibration to the cab. I've done it before and did not like the results. IMHO, leave them for the racers.
I agree with VanGo.
A buddy of mine put in some high dollar motor mounts on his acura. Right away he said it was vibrating alot. I got inside his car and it shook real good.
Opt for the OEM. Just my opinion though.