MUNICH, GERMANY - To the casual observer, the updated 2008 BMW 5 Series will appear identical to the 2007 model. What’s different are some very slight exterior modifications, updated engines — including one entirely new power plant — and more standard and optional comfort features, according to www.boston.com.

New exterior trim included in the 550i’s optional Sport Package gives the car the appearance of the more expensive, performance-oriented M5, but without the additional $20,000 that the 500-horsepower rocket commands. I tested the new 550i with the Sport Package, which adds 19-inch wheels and tires, more aggressive front and rear body panels and black tailpipes.

There are three distinct 5 Series models. The main difference among them is what’s under the hood and how it impacts the driving experience. The entry-level 5 Series is the 528i, replacing the 2007 525i. The 528i is powered by a 230-hp inline-six-cylinder engine.