High mileage on a 97 Taurus

Hi. I'm new here so I don't know if this question has come up before, but I'm thinking of buying a 97 Taurus GL wagon with about 156,000 miles on it. I was told by a couple of people, that you can get some very high mileage out of these cars and have heard of them going upwards of 300,000 miles reliably. I believe the tranny was replaced by Ford, about at about 100,000 miles.
Is it true that the taurus is a good vehicle when it comes to high milage, and I'm also wondering if anyone has tried to replace the oil in theirs with a full synthetic to improve engine life?
I've always driven F-150's but don't need the power or cargo room any more, so the taurus seems the way to go.
Thanks for any help.

the engine will run forever, but unfortunately, you'll be replacing transmissions every 70-90k miles.

I personally wouldn't try to switch to synthetic in an engine that already has 156k on it and hasn't been on it before, theres a good chance that would cause leaks.