Can anyone describe the basic differences between the various Naim replacement 321/729 cards? I've listened to both the NJ cards and the RSL cards on a friends system, and thought the RSL cards sounded the best. Although reading a few of the old posts on this fine forum, I see most like the replacement cards but a few choose to keep the Naim originals, even if they own the 32.5 which of course didn't have the time aligned cards! Any brief thoughts? Wondering whether to buy some or just buy a new amp. Currently got a 62/180/Hicap set up. Like the Naim sound, for some reason more modern amps I've tried sound harsh in my listening room, but Olive Naim not so.