I have one of thier cheaper metal ones, have fitted them to sierra's before and they do help a lot especially over uneven surfaces, and much much better under heavy braking.
Mine was supplied with stupid screws, but I fitted through bolts with large washers underneath the strut top.
I had hassle off them STRUTBRACER, with constant delays and excuses as to why I had not received it, then claiming they had not cashed the cheque and would send it back, but they had cashed it as I pointed out to them.
I waited 8/10 weeks for mine, and I have read elswhere it is not an isolated case.
tabetha