Just for the record (it seems I missed the follow-up posts in this thread earlier), I actually was speaking from experience, albeit second-hand.
The springs that DropZone sold for the Ford Focus were junk. A friend of mine bought some, and the rear actually sat higher than it did with the stock springs with them in...They had horrible rates (lots of bottoming-out) and as a result of all these factors they were removed within a few months of installing them.
That's the extent of my experience with their springs. It may be anecdotal, but it isn't made-up. (dunno)