The 2010 Chevrolet HHR is a retro-styled compact wagon that comes in either LS, LT, or SS trims. Engine options start with a 2.2-liter inline-4 producing 155 hp, but a more vigorous 2.4-liter is also available with 172 hp. Performance-oriented buyers can opt for the SS trim which offers a turbocharged 2.0-liter engine with a robust 260 hp. While most HHR models utilize a front-wheel drive setup and a 4-speed automatic transmission, the SS version offers a 5-speed manual. Inside, the HHR provides a fold-flat front passenger seat and a 60/40-split-folding rear seat for added versatility. Key features include an available sunroof, OnStar telematics, stability control, and a trip computer. For entertainment, Chevrolet equips the HHR with a 6-speaker audio system featuring CD/MP3 playback and an auxiliary audio jack, but a premium seven-speaker Pioneer system is an option for LT and SS trims.