that's a double edged sword answer:
on the one hand, if your goal is "performance" of an SVT, then you can CLOSELY match it by picking up a V6 base model, grabbing some SVT bits (Upper intake, lower intake, Throttle body, exhaust, etc) from a parted car and be right there, almost.
However, if your goal is SVT looks AND performance, then it is simply cheaper to buy one (at the INCREDIBLY low prices these days) than to purchase the full body kit, interior, gauges, etc..
If you planned on far surpassing stock SVT performance anyway, you'd need a new 3L engine instead of the stock 2.5 and thus you lose a lot of the "SVT"-esque feeling of the car anyway and many Purists will say at that point its no different than a regular Contour. However, I feel that even with a new engine, my SVT is an SVT because of the VIN, and thus I would still choose the SVT even if I planned on a 3L.
My personal response is: the price difference between an SVT and a V6 base model is either SO small or non-existant (I can find an SVT that is CHEAPER than a standard V6 a lot of times) that it doesn't make sense to go the other route, unless you need specific body parts because you already own a standard v6 and want a parts car, etc.
get the SVT..
Check the classifieds forum (directly underneath "common interests") and your local region (southeast, great lakes, etc) forum for their sale ads.