hmm.. I have the K&N 57i induction kit for my focus 2.0 .. and I've got a little cold start / idle problems, though they apparently were due to a broken carbon filter unit (pic: http://rit.cc/ses/undir-hoodi-dosin.jpg if someone can tell me what that black little can is called in english, I'd be very grateful)...

Anyways, just call around to some shops, somebody's bound to have something for the focus 1.8