Yea i looked through that thread, i think H&R is the only company that has something specifically for the EX.  The thread mentions using G35 springs, G35 coupe sport curb weight is only 200lbs lighter.  I can pick up a set shipped for $50 or $60 on G35 forums.  I think it's worth a try, have the shop install one side to make sure fitment is decent.