Substantial improvements to the BMW 5 Series sedans and wagon for 2007 add a lot, but change little. The 5 Series remains a truly sporting sedan that stands out in the fiercely competitive market for mid-sized luxury cars.

Changes for 2008 represent the most significant model-year update since the current 5 Series was launched in 2003. They include mild exterior revisions, improvements to the interior and a significant power boost for six-cylinder models. The new 528i, formerly the 525i, is the most powerful entry-level 5 Series to date. The twin-turbo 535i, formerly the 530i, is the quickest six-cylinder 5 Series car ever. The change in BMW's numeric naming scheme is a result of the change in engines, but the various models and their relationship to each other remain basically the same.

Their basic character hasn't changed a bit, because every 5 Series puts an emphasis on the driving. This mid-size luxury sedan remains a true sports sedan in any of its variations, including the 535xi wagon and other models equipped with all-wheel drive. Regardless of engine size or equipment level, the 5 Series line delivers lively acceleration, precise handling and outstanding brakes. It's available with a conventional manual transmission, which is increasingly hard to find in this class.

This car has just about everything you could ask for in a luxury sedan, including the features, comfort and convenience of full-size luxury models, the sporting character of smaller ones, and a good compromise between interior space and physical bulk.

The 5 Series line offers more model choices than most cars in its class, with prices spread from the mid-$40,000 range to over $90,000. Even the base 528i boasts spirited performance, with decent fuel economy to lower operating costs. The 300-hp six-cylinder in the 535i matches some V8s, while the V8-powered 550i delivers true high performance by any definition. The limited-production M5 can out-accelerate, out-brake and out corner some expensive sports cars, with comfortable seating for five. There's a wagon for those who want more room for cargo and BMW's x-Drive full-time all-wheel drive for drivers in the snow belt.

Now familiar, the 5 Series' flared-nostril front end and overall appearance may still make it difficult for some buyers to embrace. It's still loaded with the technology that's made it a benchmark for critics and auto industry engineers alike, and some of its systems and features have a dark side. The i-Drive point-and-click control system, for example, takes time and energy to learn, and drivers who aren't willing to invest the energy, or those who just prefer things simple, might want to look at another car.

However, those who put driving satisfaction first should put the 5 Series near the top of their test-drive list.