Choosing the right Bryston amp

So it's not like the 3BST isn't powerful enough, just that the 4B will sound better? Will it sound 1500 bucks better, do you think? (I know that's a subjective call; I just want to make sure, if I go with the 3B, that it's not struggling to power the speakers. I know that can be a concern with more expensive speakers.)

The 3BST should suffice for all but headbangers who probably aren`t Performa 30 users.

Put it this way....at high levels and with significant bass material the 3B will clip before getting the most out of your speakers. Clipping is the main cause of speaker failure: bass woofer sucks up too much of the amps power and then (most often) some nasty clipped signals heat up and burn out the tweeters. The sad part about this is that just before it blows it actually sounds less loud as the coils are by that time very hot (usually the third song played too loud)...in my view clean power especially with SS amps is worth it because it not only protects your speakers but reduces the awful clipping that you sometimes get from peaks in challenging material (unlike tubes, SS amps do not clip softly and sound plainly wrong when clipping)

A used 4BST should run 8-900$ more than a 3BST,[last I looked].Your call,depends a little on how long you may keep those speakers possibly....?Good luck,Bob