Just remember Ford screwed up the whole focus deal changing things, that do not really add to the performance of the vehicle. They just made alot of focus customizers upset.
For example I have went to Ford Parts' sites, and they only have one part number for a knuckle for the 2006 and 2006. But after researching and reading about the focus on various sites, I know it not right. Thats why a 2005 and earlier lowering kit will not fit on a 2006.
But if you are stuck with a 2005 kit and it will not fit your car, you can purchase the knuckles for about $200. Then I think you would need a upper spring perch, and then the rest should work.
But I have asked, and it seems no one here has lowered a late model 2006 with a complete kit. They just use the springs.
Personally, I want matched struts with my springs, but nothing out for 2006. And honestly the aftermarket is very slow to catch up. HOW HARD CAN IT BE TO MAKE A NEW SPRING PERCH DESIGN, AND LOWER MOUNT TO FIT IN THE KNUCKLES.
I thought it would be easy to do a suspension on a focus, but Ford screwed it up. Just that one little change in the front suspension, causes 06 owners to upgrade to a complete suspension.
springs alone is not a complete suspension.