Kind of depends on your long term goals and how you use your car. From a performance standpoint, I think the conventional wisdom is the stiffer the better, and there are mounts made for pretty much each of the various points the engine & trans attach to the car. The down side of stiffer mounts is an increase in cabin noise and vibration. There are options ranging from just a bit stiffer than stock to "did you weld it in?". The smart thing to do is probably to talk to Ron at Whoosh and follow his instructions.
The somewhat less smart thing to do it to post up your plans and uses for the car, then find out what 782 others have already done and now think you should do.
EDIT: Just saw the "non-ST" part. Not sure this advice applies equally to a non-ST.