I don't know what your intended use is, if the car is modified or not, etc, etc. Many people run larger tires, making the factory spare a near useless piece of added weight to carry around (since driving on a significantly smaller tire can do serious damage to the awd system). In this case, a can of fix-a-flat, or a roof mounted spare seem to take precedent. If so, you have the huge spare tire well to use to mount a secondary battery, bank of batteries, or carve up for storage/extra battery use. Just make sure you use a sealed AGM (absorbed glass mat) battery since it will be in the car..