BMW 5 Series Preview – Chicago Auto Show: You wouldn’t know it at first glance – or even a second or third glance – but the BMW 5 Series receives styling updates for the 2008 model year. They’re very subtle, so much so that we almost had to take BMW’s word for it that things actually had changed. The same holds true for the updated interior, which features further refinements to BMW’s iDrive system. What isn’t so subtle is what’s under the hood. Both six cylinder engines in the 5 Series are updated with more power and refinement, with the most potential for fun the addition of the twin-turbo 535i, featuring the same engine as the excellent 335i coupe.