To OP,
Be aware that ext warranty does not cover bumper-to-bumper like the OE warranty does.
Most ext warranties exclude wear and tear items. Pretty much anything made of plastic or rubber is not covered.... suspension? likely not.
Read the fine print if you intend to buy one.
When I had my 1st BMW ('98 540iA), I worried about the reliability.
Indeed, it ended up an expensive ownership.
I purchased a 7yr/100K ext warranty from the dealer
(3rd party one ... BMW did not sell one at that time). It costed me $2500.
In short, I needed to spend about $2000 every year for repair (after 4yr OE warranty).
Usually, only about 50% was covered, and the other 50% came out of my pocket.
For example, the coolant pump and pipes were replaced in three separate failures.
Only the water pump was covered.
Quick-to-fix was also an issue. Pre-approval was needed.
One time, the wiper motor failed before Christmas time. It was raining hard these few days. The 3rd party company was in holiday shutdown for one week. If I wanted to have it fixed, it would have to come out of my pocket.... So, I did.
Just to give you an idea.
In the end, I doubt I got my money back considering the interest rate, etc, even for such a problematic vehicle....