I'm not sure if there's a difference between the P and non P 90 V1 packs, but I've got a V1 (March 2016 90D) -- when I got it (used, 3.4 years ago) it charged to 252 at 90%; these days it charges to 245 or 244 at 90%, meaning the maximum range has gone from 280 to 270ish miles. It's been charging to 270 at 100% pretty consistently for the past year; if anything the cold weather's given it slightly more range (now barely 272 instead of 269). But -- realistically -- the speed you drive it at, or the tires, or having the AC / heat on or not is going to have way more impact on the range than the theoretical 90%.
The questions I worry about: Can I drive 200 miles at 80-85mph on normal highways? Does it supercharge from 10% to 70-80% in 30-40 minutes? Mine still does these things, so I don't worry about if the battery is okay or not.
I worry more about the suspension that seems to be made of discount ramen. If I had a P I'd worry about coolant ruining the rear drive unit. I suppose the battery will eventually fail, but by then I'll either still like the car and dump $20k into a new battery or I won't, though I have a hard time imagining a viable replacement for my car that's less than $60k these days.