allion is a solid car but concerning fuel economy the A15 does better than the A18 i had the A18, with normal acceleration i got around 8 - 9 km/l in the city and while accelerating too much i have gotten 5.7 km/l. It is a comfortable car and has a very good resale value compared to many other cars, the maintenance is not cheap though especially for the A18 because it has the dual vvti engine not many people accept to fix the car while it has a problem. I would recommend the A15 any day over the A18 if fuel economy is important if you have any questions about this car you can ask.