The dash is dominated by BMW's double wave theme in two portions: one over the instrument cluster, defining the driver's area and another that begins over the dash center and sweeps toward the right side. Double-wave could more accurately be called two-step, with two levels in the dash running the width of the cabin. This interior has drawn far less criticism than the exterior styling, and from a functional view point it's quite effective. Moreover, the soft plastics covering the new 5 Series' doors and dashboard are handsome and rich to the touch. In our view interior materials have never been one of BMW's strengths compared to other luxury manufacturers, at least not in the company's lower series. In this regard, the 2004 5 Series is much nicer than both the current 3 Series and the 2003 5.

The 5's instrument cluster is dominated by two gauge pods, with the gas gauge wrapped inside the analog speedometer and a miles-per-gallon gauge inside the tach. For 2004, the tachometer in all 5 Series models includes a variable warning LED that circles the gauge. When the engine is cold, this LED extends to 4200 rpm, then gradually increases the rpm limit to the redline as the oil warms up.

The center of the 5 Series' dash is dominated by a large electronic screen that displays various control functions, system readouts and the navigation map when the car is so equipped. There are vents below the screen and on either side off the steering column, and the move an impressive quantity of air with minimal fan noise. Cupholders for the front seats are located to the right of the center console. They work better than those in most European cars.

Between the front seats, just behind the gear selector is a big aluminum knob that generated as much controversy in the 7 Series as its exterior styling. This is the master control for iDrive: the computer interface that can operate virtually everything in the new 5, from stereo to climate controls to telephone to navigation. The control knob is easy to locate from the driver's seat without a glance and with each move of iDrive, menus appear on the video screen. The problem is that it can be confusing to use iDrive to wade through various menus and finally get to the function that needs adjustment. At best, it's difficult to master.

BMW claims that it has enhanced iDrive for the 5 Series using what it has learned from the system in the 7. "Enhancement" amounts to a new button, located right behind the iDrive knob, that opens the first menu (5s with GPS navigation have two of these buttons, with the second launching the nav system). In the 5 Series, the iDrive control moves in only four directions, as opposed to eight in the 7. Once you understand it, iDrive begins to feel like second nature, but even this "simplified" version takes some effort to learn.

At least there are separate, conventional controls to operate the stereo and climate settings. These most-frequently adjusted systems can be managed without using iDrive, and information is still displayed on the electronic screen. The 5's heating and cooling system has been improved for 2004 with new features, including more sophisticated humidity control. There's a temperature-controlled storage compartment in the console for snacks or drink cans. Rain-sensing windshield wipers are now standard.

New technologies include BMW's first optional head-up display ($1,000), which is offered only on models equipped with the nav system. The HUD projects a six-by-three inch rectangle on the windshield, focused so the display appears to be at the end of the hood, rather than right on the glass. Using iDrive, the driver can adjust the HUD's intensity and the information it displays. Options include road and engine speed, various warnings prioritized according to urgency, cruise control settings and navigation instructions.

The 2004 5 Series are available with radar-managed Active Cruise Control ($2,200). When the road is clear, it works like conventional cruise control; when the car closes on traffic, the system adjusts the speed of the car to maintain a following distance set by the driver.

One hint of the previous-generation model's advancing age was a cabin that seemed increasingly cramped compared to more recently updated competitors. With the 2004 5 Series, the modest increase in exterior dimensions translates to improved packaging inside. Front passengers get a half-inch more shoulder and head room, but the improvement is more obvious in the back, where there's more than an inch more shoulder room and two inches more legroom. This increase in cabin space puts the 5 Series on much better footing with key competitors like the Mercedes E-Class, Audi A6, and Lexus GS.

The high rear deck of the new 5 Series sedans results in a 26-percent increase in trunk capacity. With 14 cubic feet of storage space, the 5 Series moves from the bottom of the mid-size luxury class to the higher end. Load height is just above the rear bumper, and the 5 will accommodate even larger items with the folding rear seatback, which, oddly, is a $475 option. It's hard to imagine a buyer not wanting the flexibility the folding seat offers, as the seat can be locked to prevent access to the trunk.

High-tech safety features are a big draw for high-end European sedans, and with one exception the 2004 5 Series delivers. Inexplicably, side impact airbags for the rear seats are a $385 option. Perhaps BMW believes customers with small children still have concerns about the operation of these bags. Yet with advances in measuring and triggering devices, those concerns should fade, and the optional rear bags may come off as nickel-and-diming the customer.

Beyond that, all the occupant-protection ingredients are here. The 5's front-impact airbags are among the most sophisticated anywhere. Multi-stage inflation, shape and interaction with surrounding surfaces have all been refined to optimize protection. The head-protection airbags run from the front pillars to the rear, and completely cover body-side and window areas where an occupant's head might strike.