Mike (Bluesman) is right. I read somewhere that manufacturing a car leaves a bigger carbon footprint than it will ever leave by being driven for 15 years - or something like that. Just as the manufacture of solar panels (which save the planet by generating your own electricity etc. etc.) leaves a massive carbon footprint, so the net result is questionable. If you're going to run a car, it's more environmentally friendly to maintain an old, thirsty one like the LS400 than to buy a new, more fuel-efficient one. Plus it supports local garages/mechanics rather than giving all the business to main dealers (because of warranty terms).
Plus there's the fact that, at 6 foot 2, I can't actually see out of modern cars - the windows are so small - and they're impossible to park because you can't see the bonnet or boot. But that's another topic.