The diffence between a knock off watch and a knock off car is you don't die or get seriously injured if the knock off doesn't preform like the more expensive product it's a copy of. Chinese manufacturers need to be careful. The knock-off formula may work fine in China (and with smaller cheaper products here) but not with cars here. You will get much more credit with the american consumer for having something original and unique. Hell, when BMW came out with the new mini-cooper I wanted on just because it was unlike anything else on the road (not to mention handled like a go-kart and was a blast to drive - I did get one and loved it). If you make something unique, inevitably SOMEONE will like the styling and try the car. If it's just a knock-off you are rubbing the fact that it is "a copy made in china" (and here that is NOT synonomous with quality) in everyone's face. People will too be afraid of the car falling apart to buy one, and you will have to offer outrageously generous warruntees just to get someone to risk buying your car. (Not to mention insurance companies may consider the car unsafe and refuse to insure, or charge outrageous rates for insurance on the cars... I don't know how it is in china, but here everyone is legally required to have insurance.)
My point after my long rambling? You guys are going to have a hard enough time selling a chinese car as something safe enough for the american consumer to even consider, making it a knock-off just makes the situation for you vastly more difficult.
Just because a car might look like a Benz, BMW, or an Audi doesn't mean that it will have the same appeal. In the US there is alot of importance in the brand name. When an American sees someone in a Mercedes-Benz, they know that the owner must be successful, an imitation Mercedes will be looked down upon.
There also seems to be alot of emphasis that the Chinese imitations "look" just like American, Japanese, or European counterparts. Aesthetics are important, but there is so much more to a car then how it looks. We care about things like reliability, safety, and performance as much, if not more then looks.
Compare the Toyota Camry to the Chrysler 300. The 300 is a better looking car, and many people say that it looks like an imitation Bentley or Rolls-Royce (those two are the pinnacle of luxury cars). The Camry, while not as good looking sells almost twice as well as the Chrysler because it has a reputation for being a very reliable car.
One cannot sell cars like you can clothes or appliances.