So many automotive analogies in one day!
First let me say I respect Scott's expertise with the high-power stuff. That's why I asked if the intended use for the K-series was as sub amps. I fully intend to have my NYC daughter who loves Coney Island visit the Eldorado Auto-Skooter emporium and report back on the thumping bass, as well as the art-deco bulb-lettering signage. (That is you, isn't it Scott?)
However, the PS-series Crowns (PS-200, PS-400) were actually updated D-series amps with turn-on-delay protection, headphone/monitor output, abilityto accept balanced input adapters, and a more modern chassis design. Many say the circuitry is identical though Crown shows slightly improved power output. Regardless, they are at a minimum the equivalent to the D-series, in my estimate they are an improvement, and I've owned a D-150 since 1974, I also have two D-150A-IIs, a DC300A-II, two PS-200s, and two PS-400s. The PS amps were more expensive than the D-series and intended to replace the D-series, though that price bump actually drove more users to the D-series which "forced" Crown to continue making the DC300A-II longer than anticipated.
The PowerLine series was Crown's attempt, as Scott says, to enter the consumer market. As such they dumbed-down the amps and made them prettier, using the old D75A and the PS-200 and PS-400 as their basis. They included a media-blasted aluminum face along with the black, added additional output-monitor LED to indicate power output, but junked the ability to use balanced inputs, 1/4" input jacks, barrier-strip speaker connections, and three-prong power cords. As far as I know, the circuitry is otherwise the same as the PS-series.
Now to take issue with Scott's automotive analogy: The new M6 is an overweight luxury car with a fine, large engine. A shame they put it in a huge, fat, soft car that relies on electronic nannies just to keep the over-zealous fat-wallet owner on the road as he surpasses his ability to drive. Think of it as the MP3 of the auto world in that it gives you only the control and feedback it thinks you need to have. The electronics are your government-bailout once you get in too deep. The stripped-down '80s M3 is the real performer whose lightweight body without accessories or nannies, and short, high-revving 4-cylinder rewarded the driver by responding to capable input and assuming you knew what you were doing or you'd not have chose such a vehicle. The visceral enjoyment from driving the first M3 (and, to some extent the FIRST M6) is akin to the basic THUMP that Scott loves from his JBLs and Crowns. That new M6 is more like the McIntosh speakers from the '70s known for their "living-room" sound. Bad shocks and all. "No highs, no lows; must be Bose", and now "high-speed with no skill; must be a computer-controlled German car!" Technology has won; we don't even need a driver anymore.
I'd still take a K2 in a heart-beat. The NEW M6 I'd trade for a barn-full of fun cars.