Originally Posted by Joey D
You don't need different struts, but just be aware that your OEM struts will fail prematurely if you have lowering springs on them. With that said though I'm not even aware of any aftermarket performance struts on the market.
Also I believe the Steeda and Ford Racing kits are similar in specs but are different products.
The aftermarket/ performance struts seem to be available only out of Europe at the moment, Bilstein doesn't sell them here for this car, but they are listed at www.european-parts.net
and other places in the B6 or B8 sets supposedly specifically for the MK3 Focus.