I am considering picking up a Tahoe, not sure of body style yet. ( I like both this and the next gen, but the wife isn't sold on picking up an older vehicle.) Were there any changes made throughout the years that would make certain years more desirable th an others. Also, how can you tell the difference between the 5.3 and 4.8 motor, is it obvious when looking under the hood, or am I to take the seller's word for it, short of decoding the VIN?