The 2013 Infiniti M sedans, while they may drive with close to the verve of the compact G sport sedans, have one very significant difference: They have usable back-seat space. The M37 and M56 also offer a smooth, refined ride, as well as top-notch interior refinement and a roomy trunk.
Front seats are exceptionally comfortable in the M, with both the driver and front passenger get ten-way power seats. There's good head and shoulder room, too, minus a little width for the thicker center console. In back, the seats are really well contoured for adults in the outboard positions, although the tall doors and rear deck can give the rear occupants a closed-in feel. Overall, while the tallest passengers might find it a little light on headroom, the M sedans don't sacrifice rear-seat comfort for looks, as do the but the 2011 M doesn’t sacrifice rear-seat comfort for its looks, as do the Jaguar XF.
The M sedans have a relatively large trunk--even though the volume number isn't spectacular, at 14.9 cubic feet, because it's not all that long. Hybrid models do sacrifice some of that due to battery storage (they have 14.9 cubic feet). otherwise there's good cabin storage, with a shallow-ish console augmented by a deep glovebox.
One of the things that the M37 and M56 do have in common with the smaller G sedans is that there's a bit more road noise than you might expect in a luxury car--even though Active Noise Control is included in all models. The V-6 in particular seems vibration-ridden. M35h hybrids, on the other hand, use a version of the somewhat smaller, smoother 3.5-liter V-6