I don't know what it is, but my car seems to eat top-mounts. One of the ones I fitted at Christmas is ruined already. Are there any uprated ones available for the 20VT?
how do you know if your top mounts are knackered ?
I've never changed mine....perhaps I should !
Crashing over bumps, and clonks from the top when the steering is turned. The steering can also feel not as smooth as it should do but you will probably need to jack up the front to notice this.