I drove my friend's Cervo 660cc turbo with tiptronic transmission, according to him it gave him average of 13-14 km/l with light foot with ac in city while i have vitz 1000cc normal version which gave me almost same mileage in city with ac and on highway within the limits it gave me 17 km/l, but driving a 660cc car it was like lagging in all gears with ac on, i feel lag even in vitz but its only in first two gears, in my opinion, atleast go for 1000cc car for better performance