When I bought mine I asked Lexus about durability. They said "We don't really know." (Beautifully stated.) They told me (that being 9/01) that the highest-milage LS in the midwest region still in their system was at
240,000 miles and had got there "mostly" on routine maintenance. They also said the highest mileage LS they knew of in the US was at 320,000 miles with no major repairs.
I saw an article somewhere a few months ago that one of the very first LS 400's had reached 500,000 miles and the owner planned to keep driving it.
My LS at 55K is about due for tires, and the dealer says the rear brake pads are 40% worn and the front, 30%. No other detectable wear.
While most American cars don't turn 300,000 miles I don't think they're really all that bad. I put 218,000 on my '85 Mustang GT before it was totalled and it was still strong and sweet with no engine overhaul. The '65 Buick Wildcat my father bought new has never had an engine rebuild but is still smooth and will still light up both rear tires. One Saturn was recorded at 300,000 miles a few years ago. Saturn got some publicity out of it ... the first thing that wore out was the driver's seat. And the highest mileage ever recorded by any car was by an American car - a '63 Plymouth ran just over 1,000,000 miles before it was totalled by a drunk a couple of years ago.
I'm old enough to remember when a good car with 60K on the clock was heavily worn, and at 80K most cars were about run out.
I have a maintenance manual written in 1911. It remarks on the greatly improved durability of modern cars, saying that if well maintained they can be driven through an entire season without an overhaul.
--Pete