I thought that in Europe you bought gas by the Liter. @ $6 a liter it is going to be pretty pricey. Besides it's not like they can drive very far.
Good luck on the economy. Food for thought, I had an 87 Buick Le Sabre that was getting ~35 MPG after some minor cleaning of casting marks and port matching. Before that it only got about ~25 MPG. Damn thing was falling apart and had to get rid of it.
I'll be doing the same to my X after my warranty is up, but that's a ways off. I'll pay the extra in gas to stay under warranty until then.