I get an average of 450 km in the city to a tank....279 miles. Not great but it's spirited driving, I baby my car but I drive it like its meant to be driven. That said, I came across a product called EcoFuel Saver. It's a little 60mL bottle you dump in your tank before filling up and it rearranges the molecular fuel structure making it easier to burn. Easier to burn = more complete burn = more efficiency.
Your supposed to run it for a full 5 tanks. I just finished my first tank and without a word of a lie I did not change my driving style once. I ended up with 592 km (368 mi) city driving. That's a whopping 142 km (89 mi) increase! I wish I had a way to actually prove this to you guys because I know I'm gonna get haters thinking that I'm just making this up..I'm not.
I will run it for the full 5 tanks like suggested. I also noticed near the end of the first tank that the engine idled a ton better, and the acceleration was way smoother.
I don't know who sells this stuff in the States or if it's even available down there but Canadian Tire sells it up here.