Seeing that, the RS4's would look best, very smart indeed. 40mm drop and job's a good 'un. As you say, any lower and you might well start making life more difficult for yourself.
And sorry mate, I just hate all this Lexus light rubbish. I think they look cheap and nasty, and like some sort of droopy eyed retard. Stick the originals back in - I think Seat did a pretty good job themselves.