I own a pair of B&W 603 S3 speakers for my fronts. But as i still have time to return them i was pondering wether the new 604 speakers would be worth shelling out for. Mainly because of the larger drive unit and innevitably improved mid range with music. But the problem is...My amp is only a sony STR-DB940, now 6 months ago this seemed great as i was still only a beginner, but is it powerful enough to drive the 604's and really do them justice in a small-medium room??? I don't have much clue when it comes to matching a reciever to speakers. For the 603's it works a treat. Don't get me wrong, they are brilliant speakers especially considering their in a small bedroom, but it was just a thought.