Set to slot into the lineup between an upgraded 335i and the M3 when it goes on sale in March as an exclusive for North America, the 335iS runs a tuned version of BMW's N54 engine, as found in the recently unveiled Z4 sDrive35iS, coupled to either a standard six-speed manual or an optional Getrag-engineered seven-speed dual-clutch gearbox.

The twin-turbocharged 3.0-liter inline six-cylinder engine of the 335iS adds a special software package to bump power to 326 hp and lift torque to 332 lb-ft--or to an even gutsier 369 lb-ft for short periods via an overboost function that unleashes added turbocharger boost pressure.

BMW puts the new 335iS's 0-to-60-mph time at just 5.1 seconds in standard guise, or an even sharper 5.0 seconds when running the optional dual-clutch gearbox. Top speed is increased by 20 mph over the 335i, taking it from 130 mph to 150 mph. A picture of BMW 3-seriesBMW The BMW 3-series line has received a moderate update for 2011.

In other changes to the facelifted 3-series coupe and convertible lineup, BMW upgraded the 335i. It receives a new N55 engine running a single, twin-scroll turbocharger in place of the twin-turbocharger setup of its predecessor, albeit without the performance software package. Power and torque remain the same as on the existing 335i, at 300 hp and 300 lb-ft respectively, with the cutout pegged at 7,000 rpm. Official performance figures put the 335i coupe and cabriolet's 0-to-60-mph time at 5.3 seconds in standard six-speed manual guise or 5.5 seconds with BMW's optional ZF-engineered six-speed automatic. Top speed is limited to 130 mph.

All 2011 3-series coupe and cabriolet models receive revised exterior styling. The changes are subtle, extending to the traditional kidney grille, bumpers, lights, exterior mirrors and wheels. They also feature a similarly subtle interior upgrade that includes a new multifunction steering wheel and dark burl walnut wood.