Krazy, you need to look at the other factors other than just fuel economy. Like engine life, general maintenance, and resale value. Lets take the Cummins 5.9 for example, 500K expected life before reduild, use syn. oil and do oil changes every 10k-20k pending an oil analysis. Sorry for the rant, but i wont be going back to a gasser any day soon. I get 18-20 around town and about 23 on the hwy doin 75-80. Its gets even better if you dont have a heavy foot like i do. And performance mods do increase fuel economy.

Jim