Hello darkhayz,
Since i've been mentioned a couple of times i thought i'd better make my comment. Don't be any means fit the fiesta 1.4 springs to the ST, people have done it, and the higher front axle load (860kg versus 820kg)results in a drop of around 50mm. The Eibach springs i have fitted are approved for use on the ST and are the same springs used for the diesel fiestas (part no 10-35-010-02-22). This results in an acceptable drop of 35mm, which looks perfect and sharpens up the handling no end. However, as you've read, the ride does firm up a tad, although i wouldn't say it's as bad as Parksey and Pinkrinse may have you beleive.