i'm trying to decide what surround speakers i should get for my 7.1 set up, already decided on the top of line polk fronts and center. My question is, i have not heard the lsi f/x surrounds, only the fxi5's. But i'm buying my system and plan to keep it for a long time! Wondering if i'd notice a big difference in the two pairs? I am in need of one pair for rears, and one pair for side surrounds. Let me know your thoughts, whether it's worth it to spend the extra 400 per pair and get the lsi fx's over the fxi5's. Thanks guys, oh yeah, my amp is onkyo 100 x 7chan, and sub will be a svs PB12-Plus/2 Thanks!