That sales tax exemption is nice, but you will always regret not having that extra range if you downgrade to an LR+.
If you actually always got the EPA rated range for your SR+ (something like 240mi) then it would not be a problem, but from my experienc
e (and others on this forum) you can really only count on a couple hundred miles of range for your LR AWD (with an EPA range of 310 mi).
Why? Well as a rule you only charge to 90%, which puts you down to 278 miles. Then in general driving in Puget Sound I average maybe 85% of the EPA rating, which puts you down to 236 miles. And you usually want to leave a cushion of 20-40 miles, so right away you are at 200 actual drivable miles. And in 30 degree weather that 85% efficiency can go down to 60%. So it won't be long before you miss that extra range cushion that the LR gives you. Especially here in WA where large sections of the state have no supercharger coverage (try driving the North Cascades highway, or even around the Olympic peninsula with side trips).
Remember that once you take delivery, you can never change your mind and 'upgrade' that SR+ to an LR .by just paying the $10 difference, so better to eat that extra sales tax and enjoy the 50K you plunked down on the car
).