Yes. Adds 4 years and 50K miles. $200 deductible (but you can stack up multiple things on one visit). And if it takes multiple visits it still all goes under that first $200 co-pay
Price goes up to $5300 if not bought with 180 days. You can purchase it up until the original warranty expires.
You can only purchase it on Model S/X and you have to purchase it at the service center. Might be only available to original owner (I forget).
You do get credit if not fully used if you trade early and it is transferable.
I bought it.