Chevrolet's new Venture minivan will start at $20,495 (3 doors, regular wheelbase) and range up to $23,269 (4 doors, extended wheelbase). Pontiac's Trans Sport will initially sticker between $21,049 and $23,939, while Oldsmobile's Silhouette will start at $22,245 and range up to $26,805. That positions them well above base prices for both the Dodge Caravan ($17,815) andWindstar ($18,995), which does not offer a second sliding side door. GM counters that its engine, the 3.4L V-6, delivers more horsepower (180) than its competitors, which range between 150 and 170 hp). Chevrolet officials say they already have 30,000 orders for the Venture. They expect the highest-volume version of the Venture to be the extended-wheelbase LS 4-door, which will be popularly equipped at $24,319.