[ausias]

1.6 L4 petrol engine of 100 bhp are awful ones, bad overtaking, low torque, great fuel consumption. 1.2 L4 TSI 100 bhp, is far better in all the aspect. Turbo lag? When was last time "you" drove a Turbo Engine. Ferrari F40 biturbo was slow? 1.5 v6 Honda F1 900 bhp or even more outside F1 regulations was slow?
Fuel economy is not only a engine size problem, aerodynamics and gear ratios allowed good improvements even on big blocks.
My first Turbo car was a Variable Geometry Turbo Diesel and I will never buy an engine without turbo, compresor, vgt or biturbo. The only time I felt a good torque was in a BMW 3.0 v8 215 bhp, all other cars were slow on overtaking, slow on 50 mph to 75 mph.
A TurboDiesel of 150-160 bhp is capable of overtaking on road speed on the same time than petrol atmosferic 200 or 220 bhp. Average power on a Turbodiesel engine is higher than average power on petrol atmomspheric. It's easy to explain and test to end consumer, Advertesiments, Test drives and so on.

Maybe ther is Turbo-lag on a Mitsubishi EVO XI 2.0 Turbo of 400 bhp, but engines like 1.4 TSI with compresor and turbo, or biturbo ones, or vgt or with smaller turbos. Or Toyota Supra Turbo or non turbo ones 3.0 v6 or 2.0 the big torque improvement and 30 or 40 more bhp, made the turbo ones a good cars on fuel consumption and performance even compared with actual cars. I thing there are not any Toyota so Sportive and with so low consumption. cd=0.32, low height, good and efficient engine, autoblocking rear differential, good 0 to 62 times of 6 s or less... on highway you could cruise at 34mpg or down to 5 mpg on circuit.