<ul><li><a href="http://www.topspeed.com/cars/audi-q5/ke1666.html">http://www.topspeed.com/cars/audi-q5/ke1666.html</a</li></ul>

...which makes diesel once again significantly more cost-effective than premium gas.

Typically the TDI is (at least) 25%-35% more cost effective regarding fuel mileage than a gas engine. The price difference between 91 and diesel here in CT is now just 12%. As the price of gas rises, assuming diesel rises the same absolute terms, that % keeps dropping. The short term blip of diesel being less cost effective than 91 may be over. And certainly for the longer term outlook diesel should remain more cost effective than gas.

I let my dealer know yesterday when i dropped by that I was not happy Audi has not announced a TDI for the Q5 in the US. Hopefully this message will be repeated at other dealers.

All US diesel outlets are required by federal law to provide the ULSD (ultra low sulphur diesel) at 15ppm sulphur. All diesel engines manufactured after 1/1/2007 (emphasis on manufacturing date) will run ONLY ULSD. SOME truck stops still sell LSD or 500ppm sulphur. Truck stops are actually a better source of diesel than some auto only stations. Diesel can absorb water unless it's constantly moving in the tank. A truck stop sells a LOT more volume of fuel and thus will generally be a better fuel quality than some auto diesel stations. Most truck stops have a "small" vehicle fueling station that provides diesel from an auto friendly nozzle opposed to the high volume (aka fire hose) truck nozzels found in high volume truck stops. I run a 40ft diesel motorhome (a whopping 6.5 miles/gallon) and a Chev diesel truck, and spent 20 years working in the petroleum industry. Diesel is diesel is diesel. Just change the filters as required or stuff stops flowing.