All the cars here are compromised animals. The Cadillac's back seat is the roomiest of these three, but it is too soft and flat to provide sustained comfort. The Cadillac's curb weight of 3850 pounds is only 25 pounds more than the Audi's, but the CTS-V is more than a foot longer and far more spacious inside. The BMW is fourteen inches shorter than the Cadillac and far smaller inside, but at 3415 pounds, it is, at least, a lot lighter.
Not surprisingly, the heaviest, most powerful car here, the Cadillac CTS-V, returned the worst mileage during the road and highway portions of this test: 10.2 mpg. The significantly less powerful Audi barely bettered the Cadillac at 10.9 mpg. The lighter BMW managed a winning 12.8 mpg, but that could be because it got a bit raucous at high rpm, so we operated the engine more slowly overall than the other cars'. The EPA says to expect about fifty percent better mileage in the city for all three cars, so it is possible that we were in more of a hurry than the EPA was when testing.
The lack of economy doesn't end there; none of these cars will deliver the maximum impressiveness to the neighbors available for $50,000. That money would buy you a BMW 5-series, an Audi A6, or a Cadillac STS-all larger cars. But if you're considering our trio, you couldn't care less what the neighbors think. You want to get from A to B quickly, or maybe even just get from A back to A and have a bit of fun in the process. Because of this, the S4 falls behind the other two cars in this test. It is an excellent cruiser, and viewed as an A4 with extra power, it is a perfectly nice vehicle. But viewed as a sport sedan, it comes up short. Liven up the steering, bias more power to the rear axle, firm up the damping, dial out a bit of understeer, and you've got a contender.
The CTS-V is a bit rough around the edges, but it delivers grins and gadgets aplenty. It might make you feel like a Duke boy, but at least it is more Luke Duke in a suit than Bo Duke in dungarees. While both the S4 and the CTS-V have unique appeal, the clear winner among these three is the BMW M3. It is all the fun of the CTS-V with all the quality of the S4 and a heaping helping of refinement to top it all off. The M3 is the one that we'd own if we had the means.