I'm considering upgrading my speakers to a set of either B&W 683's or Focal Chorus 726's and I was told that my Oknyo tx-sr602 would not do well with these speakers. I know that it's not the best, but will it work? The only reason I ask, besides their recommendation, is because looking at their specs they both can dip down to near 4 ohms even though they are 8 ohm compatible. Also they recommended that I get an amp to run out of my receivers pre out. Would this be worthwhile or is there something better I can do if my receiver is not up to par? Thanks for any info.