I have recently done some very rewarding upgrading to Marantz PM6004 with Monitor Audio BX5. These have made a huge difference to the sound quality from my Project Essential and Kenwood DP-M98. CDs sound great but given that this CD player is 23 years old would I get a worthwhile improvement in sound quality if I laid out £300 on a Marantz CD6004? System is in a large room and I also have Chord Crimson Plus interconnect and Chord Carnival Silverscreen speaker cable. I have read that the PM/CD 6004 is impressive but not sure if quality will leap. Any ideas?