This last weekend I listened to the 400cx driving KRELL LAT 2s pinched-out at 80Hz while a pair (yes, a pair) of KRELL Master Reference Subwoofers handled the bass from 80 down, and it didn't suck. We didn't have a 300c to compare, and the 400cx was under 48 hours young. It does run hot like FPB product always has, and it was every bit as smooth, incredibly dynamic, and detailed as previous product. The only shortfall, in my jaded opinion, was the fact that we were using a DVD Standard and an HTS II (albeit CAST from the HTS II) up front. I feel there is no substitute for the KRELL 28c/KCT combo in such a system, and it was noticeable. The CAST II catches up to the CAST circuitry already present in the 28c, KCT, MRA, and MRS. The only upgrade to the 25sc, 28c, and KCT is a sliver center pillar top trim piece like that on the top and bottom of the center pillar of the X Series amps. The new cosmetic looks good, but it is subtle.