As far fuel economy is concerned
I owned 2010 gli and drove it uptil 2016 with massive 220,000kms mileage on odometer. It used to give 11-12km/l within Lahore and 16 on 100km/h and 14-15km/l on 120km/h.
I purchased 2016 1.8 cvti cruisetronic, and I have driven it 61,000kms till now. If I floor it with full pedal all the time within ciTy than it gives 8km/l.
Within city in normal driving it gives me 11-12km/l
On 100km/h it gives 17-18km/l shocking but yes.
On 120km/h it gives 15-16km/l
On 140km/h it gives 13-14km/l
On 160km/h it gives 11-12km/l 
Driven 61k kms all by myself.