Yes it is available. I have used it on my P100DL and can feel the difference. I believe the quoted time is 2.8
that's what i was thinking.... if Tesla says 2.9 for the X-P100D, then i'd imagine the L+ would shave a tenth off of that and get down to 2.8.
but is it just a tenth? the S went from 2.5 to 2.2. might the X get into the 2.6 or 2.7 range?
i'd love it if someone (like Motortrend, or anyone with a Vbox) would spec out a lightweight X (let's see.... 5-seat config, 20-inch wheels, that's about it) and run it at high altitude.
goes back to a basic question i have.... a loaded P100D X or S both cost about the same, $160,000. so if the S runs 2.3 and the X runs 2.8, then basically choosing the X over the S means giving up a half-second in the 0-60, but gaining so much more size, room, falcon-wing doors, automatic front doors, helicopter windshield, newer design, etc, etc.
i debated a long time between getting my third Model S or switching it up and getting an X. after an overnight test drive which quelled any concerns over ride quality (i think the ride quality of the X is fantastic and indeed quite sporty. almost identical to the S now that there's no Performance Plus suspension available anymore)
... the answer it obvious, the X wins! i'm sorry, but the diff between 2.8 and 2.3 is just not that noticeable. both slam you back in your seat and give you a thousand times more power/speed than you will likely ever need.