Ok the thing is, people are getting more and more conscious about getting fuel efficient / small / compact cars these days. The thing is, how much petrol the car consume most importantly does not depends on the car or the engine size BUT the way you drive the car.
Now, how can you prove that: Well I was watching Top Gear the other day, and they tested the Toyota Prius (most acclaimed fuel efficient car) agaist BMW M3. The cars were tested on a uniform track where Prius was forced to run at the maximum speed where as the M3 was only suppose to follow the Prius (meaning ofcourse M3 running at lower speed as compared to the Prius). At the end of the track, both the cars travelled the same distance and any guess which car was most fuel efficient? Well the Prius had a petrol consumption of around 17 km to the gallon and BMW M3 of 19 km to the gallon.
Basically what this means is that rather than changing the car to get more efficient fuel economy you should first consider changing the way you drive first. There's a totally different thingy about how drive fuel efficiently for that google it lol!
Oh yeah btw...for the smelly bunny chicken manchurian :
"I would neva leave you neva cuz foreva is foreva"