2 post vs 4 post for long term storage

I've had all kinds of lifts, the 4 post takes up too much floor space when the vehicle is in the air, while the 2 post leaves both the front and back of the shop space under the vehicle totally clear and useable.
My research showed my 2 posts being a mere 2 inches wider than the 4 post.
Some 2 posts ask for extra/harder concrete for base, but extra stability may be easily added with a 2 ft extension of the footprint, shown by the instructions.