ford increased the compression on the svt with different pistons, used forged connecting rods to enable to engine to better withstand the higher rpm range, installed oil jets to spray the underside of the piston for piston cooling and cylinder wall lubrication. they used a better flowing cylinder head with variable intake cam timing, a two stage variable runner length intake manifold, and a tuned 4-2-1 exhaust header and more aggressive camshafts. to get svt-like performance (at least as far as hp/tq numbers go), try these mods out...
port/polished and milled head with stage 2 or 3 cams (depends on the manufacturer which stage you'll need)
adjustable cam gears
ported 2000 manifold
65mm throttle body
SVT header kit
cold air or short ram intake
that ought to get you up in the svt range, maybe a bit higher. I haven't been following the standard zetec buildups very well, but that seems to me the way to go