using the Tesla site and my VIN it looks like the trade in is $20k. I wonder if they know it needs the new battery or if that is actually not even factoring that in
If you got a trade in estimate from Tesla, that is including the battery in its condition at the time the estimate is given. They have access to that information. We got a offer of $17k for ours with 122,000 miles and the defective not yet replaced.
I'm a Family Medicine physician in Cheyenne, Wyoming. Our Signature Red P85 was paid off and we enjoy driving it. For us, the $22K to have the latest 90kWh replacement battery, with 120kW Supercharging, a 270 mike range (up from 220-230), and a 4 year/50,000 miles warranty seemed reasonable and frankly affordable to us.
For context, my wife's 2014 Nissan LEAF would cost $9,500 to replace its 24kwh battery with a 30kWh battery.
You will find all sorts of opinions pushing you one way or another. Some seem to be wanting others to follow their lead so they can feel validated with their own decision.
Ultimately, this is a personal decision. You can't change the reality of you have an Signature Edition Model S with a defective battery outside of warranty. Of the options which exist (as opposed to options which don't) which would give you the most happiness?
Is it worth the time, effort, and costs to ship the car to Gruber Motors to see if they can more or less resurrect your battery?
Do you want to keep the car for as long as possible?
Do you want to be done with it, "take a loss" (by whatever way you want to calculate that)?
What is it worth to you to have a new, upgraded battery, with longer range, faster charging, and a substantial warranty in the Signature Edition you presently own?
You don't need to post answers to any of these questions. They are just what we asked ourselves regarding our own Signature Edition P85. I offer them only to help you find your own answers for yourself.
One of the other things we considered was what we could afford based on our personal finances. It was within our easy financial reach. That is not be true for everyone.
As a surgeon, you make much more difficult decisions on a frequent basis. Trust yourself. You are NOT a "knuckle dragger". You're an intelligent colleague who hopefully will make a decision he will be happy with.