2006 BMW M3

Editors' rating: Cars
We rate cars on a scale of 0.0 through 10.0 (see "What the numbers mean" below). The editors calculate the overall rating from three subratings, on a scale of 1 to 10, that gauge key aspects of the car. On the product review page and elsewhere on the Web site, the overall rating is displayed as a series of stars,based on a five-star scale with half stars (see conversion details below).

The rating criteria with the weightings by class are:

Comfort
(40 percent of the total rating)
This rating covers a car's cabin. It takes into account the quantity and quality of interior technical features, such as stereo systems, navigation, and Bluetooth integration. While we expect expensive cars to offer these types of devices, we give extra points for economy cars that offer these features. We judge these in-dash devices on how well they are integrated with the behind-the-wheel experience. We also consider other aspects of the cabin, such as seat and steering-wheel ergonomics and flexibility. Climate control and driver information systems are also part of this rating.

Performance
(35 percent of the total rating)
With this rating, we look at technologies that contribute to a car's acceleration, cornering, road holding, and mileage. We consider innovative engine technologies that contribute to power and mileage, road-holding technologies such as traction and stability control; and other suspension elements that enhance driving. This rating also covers hybrid power trains and how well they help increase mileage. We also consider value, giving extra credit for less expensive cars that perform at a higher level.

Design
(25 percent of the total rating)
How pleasing is the design of the car's body? Is it run-of-the-mill? Strange? Extraordinary? How well is the car designed for its intended purpose? That is, if it's a crossover, are cargo areas easily accessible? If it's a luxury car, are its cabin materials up to snuff? If it's a roadster, is the visibility good, and are controls easily used? For cars with an abundance of dashboard electronics, we consider the interface and how easily features can be accessed.

What the numbers mean

9.6 to 10.0 = 5 stars (Spectacular):
This exceedingly rare score is reserved for a product that is as perfect as it could be.

9.0 to 9.5 = 4.5 stars (Outstanding):
A product that receives a rating in this range scores high on all of its rating criteria. It succeeds at meeting all of its intended users' needs and has no meaningful drawbacks.

8.0 to 8.9 = 4 stars (Excellent):
A product that receives a rating in this range is superior in so many ways that its relatively few drawbacks are not very important.

7.0 to 7.9 = 3.5 stars (Very good):
While the strengths of a product scoring in this range certainly outweigh its weaknesses, it has some minor faults that certain users should be aware of.

6.0 to 6.9 = 3 stars (Good):
This range represents a product that is above average. Its strengths slightly outweigh its weaknesses, making it good for most uses but not a standout.

5.0 to 5.9 = 2.5 stars (Average):
A product that scores in this range is functional but unremarkable.

4.0 to 4.9 = 2 stars (Mediocre):
Products in this range are below average. They fall in the middle of the pack for most features, but suffer from a few additional major flaws.

3.0 to 3.9 = 1.5 stars (Poor):
You probably should not consider a product in this range or lower. There may be one or two specialized circumstances, however, that could justify the purchase of this product for a very low price for a specific demand.

2.0 to 2.9 = 1 star (Terrible):
A product that receives a rating in this range scores low on all of its rating criteria. It does not satisfy any of its intended users' needs and has no meaningful strengths.

1.0 to 1.9 = 1/2 star (Abysmal):
A product in this range should never have been produced. This product has no redeeming qualities and worse, may actually harm you or your productivity.

0 - 0.9 = 0 stars