A 2.8-liter four-cylinder engine comes standard in most models, rated 175 horsepower. A 3.5-liter five-cylinder rated 220 horsepower is optional ($1,000). A five-speed manual transmission is standard with either engine, with a four-speed automatic ($1,095) optional. Exceptions are ZQ8 LS and Z71 LS Crew Cabs, which come only with the inline-5 and automatic.

The Colorado ($15,695) Z85 base model comes with air conditioning, AM/FM stereo, a 60/40 split-bench folding seat, anti-lock brakes, and 15-inch steel wheels. Upgrading to LS trim adds color-keyed carpets, a center armrest with storage, tilt steering column (on Extended and Crew Cab models), cruise control, CD player, bright interior accents, and 15-inch aluminum wheels with P205/75R15 tires (on Regular and Extended Cabs; Crew Cabs roll on slightly wider rubber). It's available as an extended cab ($18,040). The 4WD versions are available in both regular cab ($18,255) and extended cab ($20,600).

The ZQ8 Sport model ($17,040) rides about two inches lower than a base Colorado, and features a monochromatic paint scheme, fog lamps, and leather-wrapped steering wheel. Otherwise it is equipped similarly to the base suspension/base trim model. It comes only with 2WD and rolls on P235/50R17 tires on 17-inch aluminum wheels. The Sport LS ($18,570) adds bucket seats and a center console, cruise control, and other amenities from the base-suspension LS.

The Z71 off-road model ($17,330) packs an automatic-locking rear differential, P265/75R15 on/off-road tires, and a Smoke Gray grille and wheel flares to complement its high-riding, off-highway suspension. (Ground clearance at the rear differential is 7.5 inches.) Order 4WD and you get skid plates, too. Again, there's an LS version ($18,600) with trim and equipment upgrades, although bench seats remain standard.

Power windows, locks and mirrors are standard on Crew Cabs and optional ($500) on other models. Traction control is standard on 2WD LS Crew Cabs, and on all 2WD Z71s but optional on other 2WD models ($295). Curtain-style side-impact airbags designed for head protection come standard on LS Crew Cabs, but are optional on other models. New Gen 6 OnStar ($695) boasts easier hands-free operation and other refinements for 2005; it's available only with LS trim. LS Crew Cabs also offer optional heated, power-adjustable bucket seats with leather seating surfaces ($1,495).

Two commercial-fleet models are available as Regular Cab ($15,045) and Extended Cab ($17,390) versions of the base-trim, base-suspension, 2WD truck. They come with hose-it-out vinyl floor mats and base cloth seating, ideal for muddy-boot applications. Bumpers are painted, shocks are heavy-duty gas-charged units, and air conditioning is an extra-cost option. They're good trucks to buy for other people to drive.