You sure about using Iridiums? Most people on the Focus Forums are using copper. TurboTom custom makes his own plugs to fit since you can't get copper and colder more than one step for the zetec and at 400whp, he needs at least 4 steps colder.
As for an ignition upgrade. Most people on the Focaljet recommend the J&S safeguard. It can do everything a MSD DIS2-4 can do but it can also monitor knock and retard timing when it senses knock/deto. Everybody who has one there swears buy it. They also make one for V6s now. Here's the link, if you don't already know.
http://www.jandssafeguard.com/Have you ever thought about running water injection? Again those guys on the Focaljet who have it swear buy it. Might be able to run more power on 91 octane with the J&S and H20 injection than without. Good numbers.
