If you have very sensitive speakers (which it sounds like you do), then the DC filament upgrade will drop the noise floor down very low. The attenuator upgrade will provide perfect channel balance and a bit better resolution compared to the stock volume pot and balance pot. The Shunt Regulated Driver upgrade will uncork the performance of the driver stage and give a quicker, more dynamic presentation with a bit more open top end.
Your Sony solid state receiver and most solid state amps will employ gobs of negative feedback, so if you ever do come across one that produces hum through your speakers, that's a good sign that it's very near to a catastrophic failure.
