Thanks for everyone's input. Sounds like I would be wiser to keep my 2006 ML 350 and not go down the road of an MB Diesel.

At first, I was concerned about the Run Flat tires and not being able to repair one and then having to replace all 4 tires due to difference in size between one new one and 3 worn ones. Not to mention that I may be stranded for a day or two on a trip while having to order a replacement.

Sounds like there are more issues than Run Flat tires though. Makes you wonder whether the "new clean diesels" with all their sophisticated technology to clean-up their emissions (high pressure fuel pumps, direct fuel injection, diesel particulate filters, ad-blue filter pumps/heaters) will be more economical to operate than a gas engine. Add to that the possibility of miss-fueling or fueling with contaminated fuel and it looks like you could be looking at a $7,000 to $9,000 repair bill to replace the costly High Pressure Fuel Pump and piezoelectric fuel injectors and other associated parts.