I agree with
@Target -- I don't think your Founder's edition will draw any premium over any other non-founder's example from the same year.
Tesla has sold 4 MS Founder's cars in their CPO program and their sold prices are in-line with non-F cars.
Here's F00022 with 51k miles that sold for $30k -- but that was four years ago.
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F00029 (47k miles) sold for $53k, but that was five years ago (2016)
Here's one more non-Founders 2012 Model S P85 that sold two years ago for $39k but with 48k miles.
This is the most recent 2012 Model S listed/sold in Tesla's CPO program. So today's prices need to be adjusted for that time.
View attachment 640662
The absolutely most recent P85 sold was a 2014 model with 55k miles sold for $36.8k four months ago. And that car has AP1 and many updated features (parking sensors, folding mirrors, etc) over the 2012.
View attachment 640663
So selling a similar Founder's car in 2021 with 85k miles? I think getting any premium for that in 2021 is going to be a uphill battle. But maybe there's a buyer out there looking for such a car. It would help a lot if you could post detailed photos and features of the car.
Good luck with the sale.