They're usualy fixed to the strut tower with bolts, and the strut is bolted solid to the centre section, the only movement you should get then is rotation with the wheel.

A normal/poly mount will still allow a little movement sideways and flexing, and more than likely in an up/down direction too, you might recognise this as banging when your wheel hops as you wheelspin.

This all depends on how strong the strut tower is though.