The engineers and designers responsible for muscle cars like the Chevrolet Chevelle and Camaro must be shaking their heads, but that really goes to show that performance can come in all sorts of shapes — in this case with a turbocharged four-cylinder under the hood., , In today's environment of supercharged energy markets that have led to record gas prices, this new interpretation of Chevrolet's fabled Super Sport badge definitely has its advantages: The manual transmission HHR SS gets an EPA-estimated 21/29 mpg city/highway, which is comparable to regular HHRs with a manual. What's more, this version of the HHR is actually kind of fun to drive, though it's not without some significant visibility and interior quality issues.