big phil at ESR does them, and also adam at Z1 both sites can be found on the main forum page
do you have a large spoiler fitted ?
the standard struts are always worse in the winter, some people have removed the weight that is underneath the plastic trim on the boot, i did this to mine but my spoiler is quite heavy so have to end up getting the uprated struts.... no more sore heads
oh and welcome to the forum
Paul