The math never works out for a new/newer car. Say 190E = 25mpg, 115/25 = 4.6gal 190D = 40mpg, 115/40 = 2.85gal. You save 1.75 gal or approx $7 per days. Say you pay $4K for a new car. It will take you about 571 days to recoup your money, or 114 weeks, or 2+ years. That is assuming NO maintenance or other associated expenses.

I would keep the same car or move nearer to work. On the other hand, it you can run alternate fuel, aka WVO, for free then it is a different proposition.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.