Well, the Arrow gets 140 knots on 150 hp (75%) with 1000 lbs useful
load, and of course it's a prehistoric cabin design, but early Bonanzas
weren't any faster until they beefed up the engine, which doesn't count
in my view of aeronautical efficiency. I've flown a couple of the
newer designs (though not the Cirrus) The creature comforts are really
fine, they fly well, the glass panel is awesome, the skin is smooth
(though I'm not sure how smooth it'll be in 40 years after sitting
outside half the time).

It just doesn't make any sense to me, in spite of all of the above, to
invest that much depreciable money in a plane that cools off every time
I reduce power, has to be preheated all winter, burns a quart of oil
every 10 operating hours, and requires a manual mixture adjustment.
Many of the changes are admittedly much more than cosmetic, but the
engine is still a fairly important component of the system.