Cosworth headers are not CARB certified. Only their CAI is for 2003-2004 Focuses. Furthermore, you will likely trigger a CEL because of the missing catalytic converter. You can run a tune or do the mechanical CEL fix to eliminate it, but you will fail visual inspection regardless.
I also suggest the Exedy stage 1 based upon your needs. The hyper single is way overkill.
2009 BMW M3 w/ VF-540 supercharger @ 5psi
2002 Mercedes C32 AMG @ 18psi