Frankly, plain jane 3.0L Duratecs are just as cheap and easy to get. An SVT owner can carry over his SVT cams, extrude Honed intake, and all mods. It will make 200-210 or more FWHP with a good tune which is equal to the only "cheap" zetec turbo Ive seen on thses boards (SEAWOLF). Further, the zetec means a new tranny (more $) and the 6 speed FSVT Getreg is not a good option in any even (weaker than MTX75 and the 6th gear is mearly a second overdrive). V6 is also smoother, sounds better, and is not much heavier.
You "might" be a little ahead cost wise with zetec after you price out forged rods/pistons/turbo for both engines then add to zetec..cost of new zetec spec tranny, other zetec mods to replace V6 mods but I doubt by much.