We didn't have the opportunity to run this hybrid through a handling course (and we suspect its owners won't, either), but in spirited driving, the M35h loses little to its nonhybrid twins. The additional weight required the use of double-piston shocks (from the sport package) and special tuning for the springs and antiroll bars. Ride quality, like other non-sport-package M sedans, is generally okay but borders on stiff -- and the suspension transmits harsh impacts to the cabin far too often.
BRAKES AND STEERING
Like most other hybrids -- and unlike other Ms -- the M35h uses electrically assisted power steering. Infiniti's engineers have something to be proud of here, since they've preserved much of the feel of other Ms in the transition. There's not as much steering feedback as in the sport-package (active-steering) M, but there's more than in the all-wheel-drive version -- and the effort builds up just right.
The brake pedal's feel is less successful, if only slightly. In normal driving, the pedal is acceptably easy to moderate. Quick applications result in a time lag while the system proportions between regenerative and friction brakes.
For most of the driving experience, though, the hybrid feels like a normal M. The engine starts smoothly, but admittedly not as unobtrusively as some other hybrids. Planetary gearset-type hybrid systems with two motors (like the Toyota and Ford systems) more smoothly start their engines (Infiniti's system uses a clutch between the engine and the rest of the driveline.) On the plus side, the sandwich-type systems like the M35h's use conventional, non-CVT transmissions and are more efficient on the highway -- and they're far less complex and expensive. The occasional small shudder on startup is well worth the tradeoff.
The M35h is very willing to keep the gas engine switched off. Infiniti says that the V-6 is off nearly half the time in normal driving, and that's not a meritless claim. During our drive loop in a preproduction M35h, the engine was off for nearly 40% of the miles we covered -- there's a clever secondary trip odometer that keeps track of engine-off miles. The figure jumped to 57% during a 25-mile fuel-economy run, which netted an impressive, indicated 33 mpg on a mostly city-street loop. Obviously, the gasoline engine is the primary source of propulsion, so it'll be on nearly all the time on the open road, but Infiniti says the engine can switch off during coasting at speeds up to 85 mph.