Performance generally comes at the expense of comfort, and with the Infiniti M35x landing last in this category, despite having the largest interior, our testing seems to support that thesis. But what might surprise you is how just a one-point difference put it there rather than the Lexus GS 300 AWD. What might surprise you further is that the least expensive Acura RL not only supplies the best ride quality in this contest but also delivers the greatest comfort. And when it comes to luxury sedans, comfort is of paramount importance to many consumers.

3rd Place – Infiniti M35x
With the greatest leg room, the most head room, and the largest interior, you’d think the 2006 Infiniti M35x would have this category locked up. Add standard equipment like a front seat entry/exit feature, Intelligent Key keyless ignition and locking, an in-dash CD changer with MP3 capability, a Bluetooth wireless communications system, and Infiniti Voice Recognition technology backed up by remote controls for the information display screen on the steering wheel, and it might seem that the M35x is the clear-cut winner when it comes to comfort. But it’s not, despite options such as climate-controlled front seats, heated and reclining rear seats, a rear view camera, Intelligent Cruise Control, and a rear DVD entertainment system.

For starters, the Infiniti offers the front passenger a six-way, rather than a 10-way, power seat with no height adjustment. But that’s only a problem if you’re not driving. If you are driving, you might discover that the driver’s seat cushion is too short and too small, that the armrests feel too tall, that the accelerator pedal and the dead pedal don’t reside on the same parallel, and that the steering wheel rim is oddly shaped and uncomfortable to grip after awhile.

If you’re going to ride in the Infiniti, don’t call “shotgun!” Grab the back seat, where ample cross-your-legs space and a tall, firm, supportive bottom cushion await. And if the M35x is equipped with the heated and reclining rear seats, and the rear DVD entertainment system is showing the latest Netflix arrival, these are the best seats in the house. Until the road turns twisty, that is.

Getting in and out of the tall Infiniti is a breeze, and loading the trunk is easy through a large opening. For a luxury car, though, there’s too much interior noise. Lots of road texture and suspension racket makes its way into the cabin, and you’re always aware of the engine and exhaust notes.

2nd Place – Lexus GS 300 AWD
Scoring less than a point ahead of the Infiniti is the 2006 Lexus GS 300 AWD, which has an interior about the size of the Acura RL but smaller than the M35x. Standard comfort features include SmartAccess keyless ignition and locking, 10-way power adjustable seats for both the driver and front passenger, heated front seats, a handy touch-screen dash display, and Bluetooth wireless communications technology. Unique to this group of luxury sedans is the GS 300 AWD’s power trunk closer. To enhance comfort, Lexus offers options such as a reversing camera, a rear sunshade, ventilated front seats, and a Mark Levinson audio system with DVD video capability. Movies are displayed on the dash screen, but only when the transmission is placed in Park.

In practice, the Lexus GS 300 AWD features comfortable seating front and rear. In fact, despite its rakish roofline, there’s plenty of head room in the rear seat. Leg and foot space, however, is not as generous as in the Infiniti. The leather Lexus uses inside the GS is wonderful, soft to the touch and upscale in appearance. Indeed, every touch point inside the GS 300 AWD is soft, though during spirited driving we found that bracing a leg on the door panel was quite uncomfortable. Also, we’re not crazy about the wood-and-leather steering wheel, which on sunny days, heats up like an electric charcoal starter wand.

Because the Lexus is lower to the ground than the Infiniti, it’s not as easy to get into or out of, especially in back. The doors open wide and the roofline is low, so clambering aboard is more of a chore, particularly in tight parking slots. Plus, the rear wheel well intrudes to a greater degree than with the M35x. Up front, secondary controls including the fuel door release are hidden in a cubby on the lower left side of the dash. If you leave this open while gassing the GS 300 AWD up, watch your knees when you step back into the car.

We also had trouble figuring out how to pop the trunk on our Lexus, which has a smaller opening than the Infiniti. However, Lexus provides four chrome tie-downs, where Infiniti has none. Note that the Lexus has a power trunk closer, but swinging the strut-supported lid down far enough to engage this feature is a chore. Interior noise is limited and largely attributable to the run-flat tires, though with the sunroof cover open there is noticeable wind noise rushing over the roof.

1st Place – Acura RL
Like the Lexus and Infiniti, the 2005 Acura RL includes goodies like power heated front seats, Bluetooth wireless communications technology, Keyless Access ignition and locking, and voice recognition technology. It also comes standard with Bose AudioPilot active noise cancellation for the stereo system, a power rear sunshade enhanced by rear side window screens, and an exclusive XM NavTraffic information system that helps to route you past rush-hour traffic jams and accident sites. And despite the fact that the Acura was the only car in this group without ventilated front seats, and that it has the least amount of front-seat leg room, we decided it was the most comfortable anyway.

Credit the Acura’s soft yet supportive, bolstered yet unrestrictive front seats for helping it to land first-place in the comfort category. We also liked its smaller-diameter steering wheel, which is good to hold, and the impressive amount of space up front. Soft, plush armrests and a concavity in the upper door panel where elbows like to rest also went a long way toward making the RL the comfort king. Rear seat passengers are also coddled. The RL shares back seat dimensions with the Lexus, but it feels much more spacious. Your legs and feet aren’t crowded in this car. Plus, the Acura comes standard with a power rear sunshade and includes pull-up side screens, too.

Entry and exit are simple, too. The steering wheel automatically telescopes toward the dash when you get in and out, and in back the Acura’s taller roofline, less intrusive wheel well, and doors that open almost 90 degrees are a big help. The trunk is easy to load, through a good-sized opening with a lid that is light and easy to swing down for closing. Interior noise is limited to wind roar from the side mirrors and some traffic noise evident through the thin side glass. The engine sounds great when revved, much better than the Lexus’s high-rev blare and more sophisticated than the Infiniti’s throaty bellow.