Springs will hold it up cool thanks. So as far as the shake it might be the motor mount. Also when I first rev up from a stop I hear I clunk sound then it goes away until I rev up again. Did that happen to u. Was it just the front mount or all of them. There are 4 mounts correct. 02 deville. I looked at all of them and there was no leaks or damage on the outside of them but looked dry maybe harden. What test I can do to make sure that the mount or mounts are bad.
I did get used good tires.