The fuel consumption on this vehicle is absolutely amazing, I've been driving everyday for 5 days now and the fuel bar only went down by 1/3 of the first bar. 1/3 of the first bar for 5 days of driving (Subang to KL and back everyday)! I average 60km/h - 75km/h when I drive. Definitely one of the upsides of having this car.

Well.. Proton can only survive in Malaysia. No innovation, how to compete?
In terms of FC, diesel wins hands down. In terms of thermodynamics efficiency, diesel wins over otto (petrol). But, in terms of racing pedigree, petrol wins since it is easier to control the combustion in petrol engine at high rev, than diesel. Diesel needs to be turbocharged to get better drivability. If compare in terms of NA, petrol wins over diesel. Diesel needs steel engine block (heavier but stronger material strength) to accommodate its higher torque (explosion) and compression ratio (typically 15:1 to 20:1, but Mazda Skyactiv-D managed to reduce it to 14.0:1 so can use aluminum engine block), petrol can go with aluminum (lighter but less material strength). Diesel engine can be flooded with some water, and can still work, while petrol engine will cease to work completely. If run out of fuel, diesel need to be bled to let the air out after refuel in order to restart the engine, petrol can just fill and start.

Each has its own merits and drawbacks in their respective areas.