what's a good medium between really stiff engine mount inserts and inserts that are too soft? actually, i don't really know what is wrong with my inserts, only that when i have a drastic change of rpm or torque, my engine clunks. when my car is off i can grab a hold of my engine and move it (although not much). any ideas on what my problem is? i don't want too much vibration, but i need to fix this problem. help....