I haveone but it is not the AM one. I got it from Harlan Custom Components. From what I haer the AM one needs "pills" to set the desired RPM but I'm not certain. Mine is mounted right on top of the steering collumn in front of the speedo.
Ford Racing has a new "Tach Adapter" that sends out a signal that shift lights and tachometers can use to get a signal on the Focus. It seems that the new electronics on these cars don't normally have a wire you can tap into to make most tachometers and shift lights work like the older cars do. If you run into trouble, you may need one of these. We're going to try it with a new tachometer on our race car in about 2 weeks.