Originally Posted by Puke
From what I have gathered from trading parts back and forth with a few guys in England I believe the ST170 is UK spec SVT. I COULD BE WRONG!!! but this is what I have been led to believe. Check out the UK ebay for ST170 and you will see Recaro leather interiors, digital climate control, headlamp washers, adjustable fog lamps, front windshield defrosters, and all sorts of neat stuff that we cannot get here in the U.S.
The ZX3 is simply an upgraded 3 door Focus, there is also a ZX5 which is a five door.
Hope this helps a bit.
I think you are correct about the ST170. I remember reading on the Mustang forum that the "ST" stood for Sports Technologies and the 170 was the HP. The same HP found in the SVT here.
The ZX3 doesn't necessarily mean an upgraded 3 door Focus. It's just the designation for the 3 door hatch. Within the ZX3 and ZX5 hatch models from '05 on there were "S", "SE", and "SES" trims. SES as you know was the top trim until the Titanium models came along in '12.