Unless you are going for the whole Shawspeed package then I woulden't bother personally, doing induction and exhaust mods will help the engine to breathe easier but don't think for the price I think you would be dissappointed in the gain. The trouble with induction cones is they can suffer from heat soak, the Focus suffers from this if you simply replace the standard filter with an induction cone in the same location so it will actually do more harm than good.

Martin