am I the only one who won't touch a third party dealer car because you can't get extra warranty?
You're probably not the only one. I'm sure there are other unwise people out there.
I did a thorough background check of my S85 that I bought from a dealer in Atlanta (and the dealer also). It was sold new as a demo car and the warranty was good until 53,000 (had 38k when I bought it). So I had 15k miles to fix any deficiencies anyway. I also learned that it was built in February 2015 so I knew it wasn't a rush job. The dealer I bought it from had incredible reviews and my conversations with them pre-purchase gave me great confidence in them. I have immense respect for them still.
I now have 62,000 miles on the car and it hasn't had a single problem. I'm $4700 (plus $200 for any repair) to the good. I'd have to spend at least $4901 in repairs over the next 41,000 miles to lose a single dollar. Given that the battery and drive train are warranted through that time, I am fully confident that the odds are on my side.
I think anyone that has a car that has had no or even minor issues through the first 50k is a moron to spend $5k on a warranty that MIGHT provide as much as $7k in repairs. Not a very good bet.
I will also tell you that if you buy a car that you think is SO bad that you need to have a warranty on it for 50k miles, you should probably consider buying another brand. I was, and am still FULLY confident that my dealer purchased Tesla Model S will roll right on past 100k miles with no needed repairs. I'll go on a nice vacation with that money.