The C-Class interiors continue to look like a Mercedes-Benz should, and for the most part, they feel that way, too. The firm, supportive seats are excellent: neither so hard that they numb the backside nor so soft that they leave occupants tired or aching. The seats in the standard luxury sedans are more traditional, perhaps richer in appearance, than those in the sport models. Adjustable lumbar support has been added for 2005, providing more comfort for the lower back. By comparison, the seats in the sport sedans look stark, but provide significantly more side bolstering for spirited driving.

Seats in the sedans and C320 coupe come standard with leather facings. The C230 coupe comes with cloth seats with manual fore-aft adjusters. The C55 AMG has its own special sport seats and premium leather upholstery.

In general, all C-Class models are trimmed with good-quality interior materials, but there are some exceptions, particularly in the coupes. Some of the hard plastics and textiles don't match Mercedes' best. Apparently the company had to account for lower prices somewhere. The sport coupes and sport sedans feature aluminum trim throughout the cabin, though the coupes have a lot more ordinary black plastic. The standard sedans and wagon feature wood trim.

The 2005 C-Class models benefit from a new instrument cluster with four gauges, replacing the three-gauge instrument cluster in previous models. A chromed-ringed tach and speedometer of identical size sit front and center. To the left and right of these are smaller fuel and temperature gauges. In the middle sits an LCD display with various system and trip functions. Fashioned in the mold of the E-Class, the new instrument cluster is shared among the coupe, sedan and wagon with minor variations. The cluster is deeply hooded and virtually eliminates glare on the dials. The backlit script is clear and easy to read.

We like the redesigned layout and style of the center stack, which looks more modern than before. Audio controls are now located in what we consider the optimal spot: above the climate control switches, which sit at the bottom of the stack. Both audio and climate knobs are large and easy to locate. The lack of some of the complicated systems found on more expensive Mercedes models simplifies things.

Overall, the C-Class switchgear is easy to use and understand, though there are a few exceptions. The stalk controls have a beefy feel with positive detents, but the stalk-mounted cruise control remains problematic. It takes time to master the system. And it's easy to engage the cruise control by mistake when trying to use the turn signals, a complaint we have with every modern Mercedes that comes to mind. On the positive side, buttons on the steering wheel spokes allow the driver to operate the audio and telephone systems and other functions without removing a hand from the wheel. The dash vents have been enlarged for 2005, improving airflow in the cabin, important on hot days.

Lighting inside the C-Class is effective, with good illumination for entry in the dark and excellent map lights for reading. The glovebox is a good size, unless you order the CD changer, in which case you lose most of it. You'll still have the center console and door pockets, but we'd like more places to stash things. Mercedes (like German automakers in general) still seems to be adjusting to the idea that people (at least Americans) tend to carry stuff in their cars. At least they've added a new pop-up cupholder in the center console.

The rear seats in the sedans and wagon offer generous space and comfort. They're installed theater style, and sit slightly higher than those in front, giving back-seat riders a better view forward without significantly compromising head room. Indeed, the spacious rear seats are one of the C-Class's strengths when compared to some competitors. The optional power sunshade for the rear glass reinforces the feeling you're in a Benz.

The rear seats in the coupes are comfortable even for small to medium adults, but the sloping roof restricts headroom. Tall people will not like this space, but short people will be okay with it. Getting back there is easy enough. The front passenger seat automatically slides forward when the seatback is flipped forward, opening up the rear compartment for entry. The hatchback design of the coupe offers more cargo utility than the sedans. The 60/40 split rear seats can be folded effortlessly, with the bottom sections flipped forward or left in place, depending on how much cargo room is needed. With the rear seats in place, the coupe's cargo area offers up 10.2 cubic feet of space, or as much as the trunk in some comparably sized sedans. Yet folding the rear seats down reveals 38.1 cubic feet of space that can be filled with much larger items.

The sedan's trunk is spacious for a car of its compact exterior dimensions. With 12.2 cubic feet of cargo space, the C-Class has significantly more trunk volume than a BMW 3 Series sedan (10.7 cubic feet), though less than that of an Audi A4 (13.4). An optional split-folding rear seat ($460) expands the sedan's cargo capacity.

The C240 wagon has exactly the same interior and exterior dimensions as the sedans, except for that useful extra space behind the second seat. With the seats in place, the wagon offers 25.2 cubic feet of flat-floor load space. Folding the rear seat down creates more than 63 cubic feet of space, or slightly more than an Audi A4 Avant or BMW 3 Series sport wagon. With the split rear seat lowered, the wagon presents a load floor measuring 66 inches deep by 35 inches wide, and it's flat for easy sliding. Lighting and tie-downs are provided in the rear hold, along with a 12-volt power point. An emergency tire sealer/inflator is standard instead of a spare, and the wagon comes with a fitted crate hidden under the carpeted cargo floor. The crate can be removed, filled with goods, and then re-stowed out of sight.