The attached picture show the new transmission mount spring on the left, and the old on the right, off my '95 V12. The old spring had sagged 3/8". 'Nuff said.

 

X305 owners report a slight gap at the bottom cushion even with a new spring in place. Which seems to be acceptable. I've got one ready with new rubbers and cushion.

Springs will also lose their spring rate over time, as my rear IRS springs showed. New is the way to go.