The "added lightness" mantra is well-known in performance circles--cutting weight helps everything about a sports car, from acceleration to braking to handling. Now, it seems to help out in emission figures as well. Lotus announced the 2011 Elise scored 46.6 mpg and a mere 239 grams of CO2 emissions per mile, making it the cleanest and most efficient gasoline-powered car in its performance category.

When the revised Lotus was revealed in February, it was announced that it would be powered by the Toyota sourced 1ZR-FAE 1.6-litre engine with Valvematic and Dual VVT-I, producing 134 bhp and 160 Nm. At the time, Lotus estimated the fuel economy and emissions improvements to be around 23 percent and 13 percent respectively. Gains were also made thanks to improvements in aerodynamics, which cut drag by four percent. 134 bhp might not sound like a barnstormer but it projects the 1,934 pound Elise from 0 to 60 mph in 6.0 seconds.

For comparison, the 2010 Toyota Prius, which takes just under 10 seconds to reach 60 mph, manages a slightly better 50 mpg combined rating, and emits 148 grams of CO2 per mile. However, it requires a much more complex hybrid system to do so, thought it has a back seat. Even if the 2011 Lotus Elise isn't the greenest car on the planet, it certainly proves that you don't have to give up fun to go green.