If you look at Fords web site for UK or Germany on the ST170 you'll see these gauges in that little spot by the speedo and tak that's good for nothing ont he american focus. Where can you get this instrument cluster?
I know they're for oil pressure and oil temperature for a fact and that they are electro luminescent (indiglo style) but will check with a Ford dealer for you when I get the chance seeing as we get the ST170 here in Oz.
I agree that it would be too much trouble also. I don't think that you can you it without the rest of the SVT cluster, and I don't think the SVT cluster is plug and play compatible with the ZX3/ZX5/ZTS. The speedo is calibrated differently (it goes up to 170 instead of 130 or whatever ours does) and the oil pressure and oil temp have to go through the ECU prior to going to the gauges... etc etc.
Too much of a pain in the ass, if you ask me. Easier to do aftermarket gauges for these readings.