Here's my idea: If you are gonna run a 15" wheel, look at getting a set of cheap used or steel or whatever that will fit. Lots of older euroFords (Tempo/Topaz, XR4Ti, etc.) also used the right offset and bolt pattern wheels. Who cares what you look like when you are racing?
One of the big Focus stores sells the 15x6 Focus wagon wheels (15 spoke) for something like $180 a set. They only weight 14lbs or so which is pretty good expecially at that price.
2004 Focus PZEV 2.3L - KW sport suspension, SP camber plates, Eibach front swaybar, FS intake, FS Stealth exhaust, 3.82 Final, Torsen ATB, Prothane MM insert, E1 CSVT wheels
1/4 mile -
15.201@89.4mph
)