Amps don't have to do with soundstage, that's an effect baked into the recording and interpreted via your speakers/room. Class D amps today, particularly the Purifi modules used in the NAD 298, are top notch. Bass response more to do with what speakers you use for bass. Personally I'd look to other implementations for less $ than the NAD but that's me. Good luck on finding someone who has used both let alone did any kind of meaningful comparison....