I only used 2 washers per bolt. They were about 1/16 of an inch thick each and I placed them on the front bolt of that crossmember. The front of the crossmember has a few bends in it to allow for clearance, and it did have it, but it was maybe 1/32 of an inch. Engine Movement+1/32 inch = bad vibes. I only shimmed it up so that when I wiggled it with my hand up and down, it wouldn't come in contact with anything. I also thought about getting a piece of rubber and jamming it in there to stop the rattle, but then thought that direct heat on rubber would cause it to melt. Out the door with that idea.

Oh, and for one of the washers per bolt I used a lock washer to make sure that it wouldn't come apart or rattle loose.