I care about saving fuel most of the time. My lead foot does the contrary though. Much as possible, I want lightweight so I wont need bigger engine to power on my car to squeeze a lot of performance, saves fuel too. Emissions like most of you, is the least of my concerns. But in somehow being taken cared of by my faithful PMS, but that was primarily to maintain my car well.
I agree that emissions is the least of my concers especially if we have a relatively newish car with stock specs.. Let me just share this article from insideline..
Emissions test car vs truck vs leaf blower (yes.. a frikin LEAF BLOWER haha!)
I won't spoil the results but it jus goes to show how far we've gone in terms of emissions control.
And oh yes, the truck they used is an F150 SVT Raptor.......
As for power vs efficiency I want a balance... That's why I ended up with a 1.6L car. Fuel efficiency is there (but certainly won't compete with 1.3 and some 1.5 cars) but when my right foot gets the itch I'm satisfied with the power.