As far as i am aware, the pre facelifts and the early (05) facelift S lines had the standard bumper/valance. Only the 06 onwards had a different lower valance and that will only fit the specific S line/S3 bumper which you can spot easily as it doesnt have the rub strip in it.
To put it simply, the valance with the grey bit on it doesnt fit the bumpers withe the rubbing strips, make sense? Doesnt to me! lol
Yeah I just compared the sline one & the old sport one & it has same lines & curves, only difference are it doesnt have any round loops to fix the parking sensors wire to given sline sensors are further up the sline bumper as the S3 is, but this is simple fix just cable tie to the plastic trims in same place anyway with some well positioned holes made into the inner lip, completely transparent as oem would be, but I'll update for sure when I've fixed into position so know if it is out by any measurements