Interesting. Just priced a max'd 2019 Model S Performance versus my December 2016 Model S P100D with most of the trimmings (I refused to pay for Full Self Driving).
Current max'ed out S Performance: $144K.
Dec 2016: $159,750 => $160K.
Because the new configurator is the Model 3-style configurator without a lot of detail, I can't tell whether the current S Performance has these things that I had in Dec '16:
Ultra high fidelity sound, subzero, premium upgrades package, enhanced autopilot, ludicrous mode, premium seats, 21" cool performance wheels and tires, 315 mile range -- all accounted for in both Dec '16 and Jan '19 configs
All-Wheel Drive -- not mentioned in Jan '19 config but I think it must have it
All-Glass Panoramic Roof -- seemingly pictured, no text to match, but I think it must have it
Red Brake Calipers -- show in picture but not listed in text, so probably part of the Jan '19 config
Black Alcantara Headliner -- not pictured or mentioned in text, I'm guessing it's included in the Jan '19 config
Supercharger enabled -- obviously must be but no discussion of whether charging is free or separately priced (I believe separately priced)
Smart air suspension -- not discussed in the 2019 config, should I assume that it's part of Jan '19 config?
Carbon Fiber Spoiler -- not pictured or mentioned in text, couldn't begin to guess whether it's included in Jan '19... I'm still waiting for the carbon fiber spoiler on my Sep '18 Model 3 Performance
Child seats in the rear -- available as an option in 2016, no longer mentioned
Glossy Obeche Wood Decor -- no longer an option, only the carbon fiber stuff that I dislike
High amperage charger upgrade -- I can charge my 2016 P100D @ 72A, nothing in the 2019 config says what it can charge at
Full Self Driving -- available as an option in Dec '16, no longer available as an option, which is for the best
So it looks to me as if a Jan '19 Model S Performance, max'd out, likely includes almost everything I got in the Dec '16 S P100D config, but at a savings of $16K. Plus maybe two years' improvement in build quality (maybe, just maybe, that's a big maybe).
Nice if you're buying now, not quite as nice if you're wondering what has happened to the resale value of your Dec '16 S P100D.
Alan
P.S. Feels like someone is building in some headroom for new, cool high-end options.