I have just returned from a 2,500 mile return trip to Venice 4 adults, 1 child and a boot full of luggage in my '93 84,000 mile LS400. The journey involved hours of cruising at 90mph+, sitting in traffic jams at 32 degrees with the aircon on full, steep mountain roads, blazing sun, torrential rain and it never missed a beat. Overall I averaged 21mpg and didn't use a measurable amount of oil.
Not bad for a 21 year old car which I suspect had been off the road for at least 5 years prior to me buying it in December and a real life indictment of Lexus quality - particularly of the LS400.