The Envoy comes with a six-cylinder Vortec 4200 engine and a four speed automatic transmission. Customers have a choice between two-wheel and four-wheel drive and packages available include the SLE, SLT, and Denali. With as many options as the GMC Envoy has, customers can specifically customize their own vehicles. Each trim on the Envoy add increased numbers of features like leather upholstery, automatic climate control, eight-way power seats for driver and passenger with memory on the driver's side, a driver information center, audio controls on the steering wheel, separate rear-seat audio controls or heated outside mirrors with turn signals. The Denali package includes a 5.3-liter V-8 which features GM's Displacement on Demand technology, which idles half the cylinders when cruising to enhance fuel economy.For 2006, the Envoy comes standard with StabiliTrak electronic stability control with Proactive Roll Avoidance, GM's electronic handling system for safety.