I drive a pair of Infinity Kappa 9's with my Sunfire Signature. I had bi-amped them with an active crossover with 2 260 wpc Yamaha MX-1000 amps, but the K 9's can drop to 0.9 ohm down low and the protection would always kick in. Never a problem with the Sunfire. I too have noticed a bit less bass, but I am not sure if that is a result of the Sunfire amp or the tube pre-amp I switched to at the same time (also Sunfire) I have a Thor TA-1000 I am going to hook up to see if it is the pre-amp or amp that is causing the lack of low end response. But I say go for it. You will never find a more powerful amp for the price. But of course be sure that you really NEED the power. I did. Let me know if you have any questions.