Seriously though, We bought both of our current vehicles after having them for an entire weekend, a Dodge Neon and the Escape. Nothing like a REAL road test to determine what sort of vehicle you're riding in.
GM is bragging about letting people have the cars for the weekend, and we did exactly that with a Dodge and a Ford dealer long before GM advertised.
Just walk in with a bank check for the purchase and make it clear that the purchase isn't complete until you are satisfied with the vehicle, say, after a weekend of driving. Just don't head off to Timbuktu with it. We filled the gas tank and drove until it was getting empty.
Oh, and expect to leave your current vehicle and the check as collateral.
With the Escape, we took delivery about 2 weeks after having it. Darn Jeep dealer wouldn't budge on the weekend thing, so he lost the sale. We let him know by driving the Escape into the lot to show him our new SUV. He was a lovely shade of green too.