I really don’t see how any of this could work.
First off you can’t have people test drive a car that are partial to any type of vehicle, this makes them overlook certain aspects that may be critical to a real review.
Second, you can’t have people test cars that work for any type of manufacturer because if they sell them, obviously they are going to hide certain faults to look for a sale or if they make them or work on them, they will most likely only find faults.
Someone who does reviews has to be totally impartial and really just a professional at it. As much as I know about cars, I don’t know that the '07 had a bad vibration at 3500rpm and the '08 model has a redesigned balance shaft. This is the type of stuff that only professionals are going to know, or care to know, because it’s their job.
Just read a Consumers Digest or open up a Motor Trend if you want to really know what’s up with a car.