Draigflag, right after I made my last post I received my copy of the January 2014 issue of Consumer Reports magazine in which they reviewed the Fiat 500 Abarth. It isn't clear to me whether it was the 2013 or 2014 model, but I'd guess the '13. It had a 1.4 liter turbocharged engine and five-speed manual gearbox. Their mileage was 28 miles per US gallon overall, with the EPA numbers apparently being 21 city/34 highway on Premium fuel. Under the comments they said it was "relentlessly noisy." Just thought you'd like to know.
As mentioned, this car is the tuned version of the Fiat 500, it's not built for economy. Ive had 11 MPG from mine. If you want the economical version, get the 1.3 diesel, the same engine I got 82 MPG with. And if they think a standard one is noisy, they should try mine, it has a stainless race spec exhaust and no silencer!
A very interesting topic - given in the uk figures for mpg are stated for urban, effectively 'highway' and 'combined' driving I have found in all my cars since these were provided that I consistently get around 20% less than the stated combined figure. Whilst I'm sure others will achieve different results, I've concluded my personal driving style and combination of local v 'highway' driving will result in this 20% less than the manufacturer stated combined mpg. Having got to 'mid life' I fancied a Mercedes SLK and decided even though I knew the mpg wouldn't be great, for once I bought a second hand car and traded a £20k saving against new price v a lower mpg..when I worked in the states some 15 years ago fuel was so cheap I didn't even think about mpg, fuelling seemed a 'pleasure' it was so cheap!
I too have found similar results, I tend to add about 5 MPG to the "urban" test, seems about right. I find small underpowered engines are the most innacurate, given that in the test they dont really take into account hills etc, Fiat's 0.9 litre twinair is famous for this.