Perhaps 1% of V-8 Camaro buyers (and 5% tops of V-6 buyers, given the generous HP of the V-6) will come close to the rated fuel economy. Owning the V-8 means using that power, not shifting at 1400rpm and driving 10km/h under the posted.
In all the km's I owned the Porsche, I did one (yes, managed to do one) tank where I drove it for fuel economy. It managed surprisingly good fuel economy, but I loathed every minute of driving it. Minivans hauled ass from me at lights and people stared as I sat in the right lane, creeping along at the speed limit.
Our Corolla loves to be driven easily. It shifts so smooth and rides so nicely. It's at it's most comfortable exceeding the rated fuel economy.
All of the performance cars I've owned were complete opposites of the Corolla. Their gear ratios were chosen for making things happen, and engines were tuned for having the accelerator to the radiator. Take the Porsche to the grocery store? Possible, but why? Heavily weighted steering was not particularly parking lot friendly (but great as the speedo bashed by 200...) and poor rearward visibility (better than many sports, though) made backing out in a sea of pickups a real pain. Nope, the Porsche was happy blasting down highway 11 from The Crossing to Rocky Mountain House. Little or no traffic, sweeping bends, good visibility and lots of room to let 'er run.