If anyone is really concerned with the quality of the air and/or the eventual depletion of the world's oil resources(won't be very long to go), why don't you go out and get yourself a solar powered car and if there isn't one ready yet, get this started by forming some company to start it going before we all languish in poverty, unemployment and economic disaster? This is really magic, the last couple of days I was racing down the freeway(in my Toyota 2.2ltr) with a bunch of University sponsored solar powered cars in a challenge race here fully escorted by back up cars, news cars, police on motorbikes and hazard-warning vehicles. They can go pretty fast like close to 60kph and maybe more like 80kph. However, they have to be extremely light, one person car with lots of roof space for the very expensive quick converter solar panels(they look like UFOs). What more can you ask? No need for fossil fuels, no emmissions, very quiet without exhausts, just keep it under the sun thats all! Problem is they cannot go up steeper slopes and may need charging up overnight and its got to be sunny for it to work. Sorry, you cannot win all the time! I drive a Euro C180 and the gas mileage is fantastic. The 4cyl of the 1994 model sounds a bit "agricultural" , but the later upgrades like the 1998 is very smooth and quieter. Maybe mine needs an overhaul its 191,000kms.