Infiniti, the high-tech brand derived from Nissan of Japan, strengthens a 2006 line of luxury and performance cars with the re-do of mid-size M45 as a screamer sports sedan, while Q45 the flagship sedan spins off a new Sport model with Rear Active Steer (RAS) controls. In all, there are six distinct products in Infiniti's Class of 2006, each posed for high-powered action and packed with plenty of premium appointments.

Infiniti's elegant flagship sedans have a powerful V8 engine mounted up front with all muscle directed to rear wheels in classic rear-wheel-drive (RWD) format. The 2006 editions include a Sport model with RAS controls, tight suspension tuning and 19-inch wheels capped by high-performance tires. RAS adjusts rear suspension geometry in relation to steering input and vehicle speed to produce uncanny agility. Power for Q45 and the Sport stems from a 4.5-liter V8 knocking out 340 hp. It connects to an electronic five-speed automatic transmission with manual shift gate and new torque converter applied.

All Qs also carry Infiniti's vehicle dynamic control (VDC) with traction control system (TCS) for computerized anti-skid control. In the five-seat cabin, world-class luxuries abound with leather sport bucket seats up front and trimwork in real wood and chrome. High-tech gear includes DVD navigation and RearView monitoring plus Visteon voice recognition.

Latest treatment for M45 has little in common with the 2003 original issue, as Infiniti's designers expanded the package and installed cutting-edge electronic controls to forge a sophisti-cated, nimble and stylish premium sports sedan. There are two versions -- M45 and M35 -- each with twin-digit tag denoting engine displacement. M45 carries the 4.5-liter V8 notched to 335 hp, while M35 uses a 3.5-liter V6 rated at 280 hp. Both spin off Sport versions with larger wheels and tires plus RAS equipment to enhance handling. M35 also offers a sure-grip all-wheel-drive (AWD) edition targeted at snow-country markets.

The cabin plants sport bucket seats ahead of a bench scooped for two with adjustable seatbacks. Leather covers seats with genuine rosewood or aluminum trim for dash and the option of climate-controlled front seats, intelligent cruise control and a deluxe Bose Studio Surround sound system.

The made-in-America QX56 is a super-size and ultra-luxury SUV stretching over 17 feet long. Despite the king-size dimensions and a huge engine in the firebox, Infiniti's SUV carries user-friendly mechanical hardware so it's surprisingly spry and easy to maneuver. Inside, there's room for up to eight on three tiers of leather-clad seats with buckets in front, a second row with bench or flip-forward buckets and a third-row bench that now splits 60/40 and folds into the floor to expand cargo space.

Powering the SUV is a 5.6-liter V8 generating 315 hp through a five-speed automatic transmission with tow/haul mode. Infiniti casts QX56 in one fully-equipped trim with RWD or AWD traction. New standard gear for 2006 includes power folding exterior mirrors with heat elements and integrated turn signals. Options are minimal -- a sunroof, DVD-based video entertainment kit and satellite radio service. (CONTINUED...)