What would make a real improvement in your enjoyment of those classical CDs would be to listen to the surround ambience mixed into the front channels in surround speakers. One of the fine HT receivers, such as those from Denon or Onkyo, can apply DPLII to extract the ambience and send it to surrounds, such as QS8s, where it belongs. This is how I listen to the thousand or so classical CDs that I have and I'd never voluntarily limit myself again to listening on only front speakers.
John's hit the nail on the head here. This would be the best upgrade/addition.
