A pickup with the highest tow rating might be considered of utilitarian use only, but the 2006 GMC Sierra 3500 features an extensive trim lineup that also offers family-friendly comfort and luxury. The biggest change to the pickup this year is a beefed up Duramax engine. The 6.6-liter V8 now gets 360-hp and 650 lb-ft of torque when matched with the new 6-speed tap-shift Allison automatic transmission. There are also a few new trim designations. Available in both rear-wheel and 4-wheel drive (Work Truck is 4WD only), the lineup still starts with the basic Work Truck, featuring air conditioning and a radio, but the Base has been replaced with the SL1 (chrome trims and cruise control). The SLE is split into SLE1, with power features, and SLE2, with power driver's seat. The SLT is the top-end trim, with heated leather seats, memory settings, and a 6-CD changer. A new feature this year for the SLT is folding extended mirrors. The Work Truck comes in Regular Cab length only, meaning one row of seats. The other trims are offered in Extended and Crew as well, with four doors and two rows of seats. The pickup bed is eight feet long on all cab sizes and features tie-downs. A bedliner and either soft or hard cover are optional. ABS brakes, 16-inch wheels, automatic headlights, and dual front airbags are standard. The 3500 also has the option of single or dual rear wheels. Besides the Duramax, there is a standard 6.0-liter, 300-hp V8 paired with either a 4-speed auto tran or a 5-speed manual. The Vortec 8.1-liter V8 delivers 330-hp and 450 lb-ft of torque with either a 6-speed manual or the Allison. Equipped with this engine, the 2006 Sierra 3500 can two up to 12,000 pounds. The effortless towing performance and powerful Duramax/Allison combo are what please most owners of the 2006 Sierra 3500, though some are unhappy with the interior materials and the dealerships.