I haven't made my mind up yet on the lease aspect.
As for the potential savings of obtaining a different car, I don't understand your response... There are thousands of vehicles that are less expensive and better on fuel than the Edge so I doubt there's much "math" invloved there. Is there not a direct co-relation between the potential number of miles I'm going to drive, my fuel economy, the cost of fuel and my overall potential savings? Yeah, I think so... and I don't need to replace it with a Kia to get that.
Again, I didn't buy the Ege to save a few pennies and I did have other choices but I really enjoy it. I own my own business and travel quite a bit so the cost and expenses of my vehicle play a factor in in my P&L statements as those costs are directly mine. In 4 months, I have put on 20,000 kms.
I bought it knowing I wasn't going to get 45MPG but if gas does go through the roof as rumor has it, I'm just looking and considering my opions.