Utility
There's no clear winner between the BMW 3 Series and the Audi A6 regarding transporting cargo.
Neither the BMW nor the Audi A6 has a marked advantage when it comes to seating capacity.
Dimensions
The Audi A6 is a little more ponderous than the BMW 3 Series.
Your wallet will hurt more every time you fill up the Audi A6 than the 3 Series because of its larger tank.
The BMW and the Audi A6 compete for the same parking spaces.
Cost
The destination charge is a standard charge for transporting the vehicle from its point of origin to the dealer. It costs roughly the same to get the BMW 3 Series to the dealership as the Audi A6.
When it comes to MSRP, the Audi A6 costs markedly more than the BMW 3 Series.
Handling
The Audi has substantially bigger tires than the BMW 3 Series. Keep in mind that bigger tires may improve handling, while narrower tires might provide better handling in deep snow.
With their similar turning circles, the BMW 3 Series and the Audi A6 indubitably handle about the same into and out of tight spots.
Drivetrain
The BMW 3 Series and the Audi have similar-sized engines, with a slight advantage to the Audi.
The BMW 3 Series could learn a lesson or two from the Audi A6 regarding pickup.
Comfort
While the front cabin in the BMW 3 Series offers a bit more head room than the Audi A6, there really isn't much of a difference.
The ampler interior dimensions of the Audi A6 make it significantly roomier for your passengers than the BMW 3 Series.
Overview
The A6 and the BMW 3 Series have the same basic after-sale protection.