From the thread title, I'd guess the intention is for lowering/looks rather than making an overly-firm pre-FL FR ride quality more bearable? If I'm guessing right, I'd agree that the consensus seems to be Sportlines are best suited.
I put Eibach Pro Kit on my FR because I was advised that they were better suited to the Koni FSD dampers I wanted, but then my aim was for an improved ride quality rather than lowering per se.