Chevrolet updated its largest sedan (and equivalent Monte Carlo coupe) for 2006 with new engines, reworked suspensions, and revised exterior styling. Front-drive competitors included the Honda Accord, Nissan Altima, and Toyota Camry. Both the midsize Impala sedan and the Monte Carlo coupe were offered in LS, LT 3.5, LT 3.9, LTZ, and sporty SS trim. LS and LT 3.5 models came with a 211-horsepower, 3.5-liter V6 (up 30 hp from 2005's base engine). LT 3.9 and LTZ sedans held a 242-horsepower, 3.9-liter V6. Chevrolet's SS models got a 303-horsepower V8 with GM's Displacement on Demand, which deactivated four cylinders under light throttle conditions to save fuel. Supercharged models were no longer offered. All came with a four-speed automatic transmission. SS models had a sport suspension and 18-inch tires; others rode on 16- or 17-inch rubber, depending on the model. Available for all Impala models except the SS was a front bench seat for six-passenger capacity. The SS came only with front buckets. Head-protecting curtain side airbags were standard in Impalas, but not available for Monte Carlo coupes. Front torso side airbags were optional. Antilock braking, traction control, and a tire-pressure monitor were available. GM's OnStar Assistance was standard. Additional options included a remote starter that turned the engine on via the keyfob, leather upholstery, and satellite radio.