I'm trying to find out how much weight the car can carry safely.
Some more details:
The Owners Manual states (in these or similar words):
The certification label attached to the
driver’s side door shows GVWR (Gross
Vehicle Weight Rating) and GAWR (Gross
Axle Weight Rating).
The GVW (Gross Vehicle Weight) must
never exceed the GVWR. GVW is the
combined total of weight of the vehicle,
fuel, driver, all passengers, luggage, any
optional equipment and trailer tongue
load. Therefore, the GVW changes depending
on the situation.
So this is the overall weight of the car, when loaded to it's maximum capacity (by weight).
If what you're looking for is how much you can carry in the car, that would depend on what the car itself weighs to begin with. This is the "Curb Weight", the weight of the car when it leaves the factory, with whatever equipment and accessories are listed on the window sticker.
The difference between the curb weight and GVWR is what the car can carry safely (based on the original equipment, including the factory-installed tires.) That difference includes passengers and cargo.
The "curb weight" might be found on the original factory window sticker for that car.
For my 2007, Subaru Canada included "Curb Weight data in its "Specifications" brochure.
Here's what it has:
Curb weight manual transmission(pounds): 2.5i = 3331, 2.5XT=3534, 3.0R=n/a
Curb weight automatic transmission (pounds): 2.5i=3375, 22.5XT=3605, 3.0R=3516
To get an idea of what the car can safely carry, subtract the curb weight from the GVWR on the car label.
If you normally keep a booster battery, a box of tools, and a full size spare tire in the car, then the additional cargo the car can carry is reduced, as these are not included in the original curb weight.
To more accurately determine what "additional" cargo can be put in the car in any particular situation, weigh the car at a vehicle weigh scale. That will establish the effective curb weight at that time. The difference between that and the GVWR is what additional cargo (including passengers) can be added.
Consumer Reports often includes Curb Weight and Maximum Load in its car data. In their August 2005 report on "wagons and car-based suvs", they listed the 2005 Subaru Outback 2.5i with a Curb Weight of 3545 pounds, distributed 54F/46R (%), and Maximum Load 900 pounds.
Note that in addition to the GVWR, there are also limits on the weight at the front and rear axles, and that the weight at each tire must not exceed the weight rating of the tire.