Krell all the way. Rock, or any other bass-heavy music, will require a tight grip on your woofers, something that only a high powered amp can provide. Forget all those puny-wattage int-amps, you need something SS with at least 150 watts, no matter how efficient you think your speakers are.
And one more thing : get some tone controls/equalizer as well. Those rock recordings need some tweaking to make them listenable.
And one more thing : get some tone controls/equalizer as well. Those rock recordings need some tweaking to make them listenable.