So I got the new drivecore XLS amps in. They are pretty sweet. 8-10 lbs for serious power. Cheap per watt, and the drivecore technology is amazing. Voltage tolerant, they don't care if your 110 is nasty, or swings from 90-125. I don't think Crown is putting enough emphasis on that aspect of these amps. There's a proprietary chip built by TI that monitors all aspects of the amplifier. Impedance, output, supply voltage, temperature, everything. They are bulletproof, literally. I got sold on them at NAMM, where an old school salesman who believed only in big iron was totally sold on them. Because of the drivecore chip. It is a revolution in amplifier control, and overcomes all the objections to switch mode amplifiers, because it responds and corrects any changing conditions. None of the other new amps on the market have anything like it.
They did, however, make 1 mistake. You can only run a high pass or a low pass on a channel. Not both. Which for direct radiator boxes is no big deal. For horn loaded subs, it's problematic. You need both. So my suggestion is still to run outboard crossovers. Use the internal limiters, (which are very very good) and all the other powerful dsp available. You can set the crossovers in the amp to steepen the slope for extra protection. For tops you don't need any outboard processing. I think the best setup for the bucks would be an xTI for subs, XLS for tops. Then all you'd need are the amps and their built in dsp.
I think it was a conscious decision on Crown's part, otherwise XLS would have killed the xTI line.