The 2005 Monte Carlo saw its SS trim replaced by the LT-not to worry, though, as those wanting the SS badge could still find it in the Supercharged SS. OnStar was now standard on all vehicles. The base engine on the LS remained a 3.4-liter, 180-horsepower V6, the LT got the 3.8-liter, 200-horsepower V6 formerly associated with the SS, and the Supercharged SS kept it s 3.8-liter, 240-horsepower V6. Mileage for the three trims was 21/32, 20/30, and 19/28 city/highway. The LS still did not have standard side airbags, while both the LT and Supercharged SS featured them. Drivers love the power and styling of these cars, as well as the interior space which makes for larger frames.