The SVTF shares similarities with all other [american market] Zetec engines, but there are differences. The head uses VCT on the intake cam for power, not on the exhaust cam like the ZX2s/Contours [not all Contours had the VCT Zetec], which was used in place of an EGR by controlling valve overlap. The SVTF Zetec also had hotter cams, raised compression ratio [10.6:1 vs 9.6:1] by means of higher compression pistons and a smaller combustion chamber [55cc for the SVTF, 58cc for the regular Zetec iirc], a tuned 4-1 header from the factory, and a Dual Runner Intake Manifold. Where the regular Focus Zetec was rated at 130hp/135trq [130hp/127trq for the VCT version], the SVTF was rated at 170hp/145trq. While SVT did a decent amount of reworking, it is a variant of the US Spec Zetec engine. The VCT version in the ZX2 also had slightly better flowing cams than the non-VCT Focus Zetec.
As for the rest of the drivetrain, the SVTF had a dual mass flywheel [to reduce some of the engine's vibrations]. It also used a Getrag 6 speed manual transmission with dual final drive ratios [4.25:1 & 2.88:1 iirc], whereas the regular Focus had the 5 speed MTX-75 transmission with a single final drive ratio [usually 3.74:1]. The SVTF also had bigger brakes and SVT 17" wheels, but the bolt pattern is the same as regular Focii, 4x108. The regular Focus also had an available 4 speed automatic trans, but that wasn't available on the SVTF. The suspension was tighter and lowered a bit as well.
