The 2025 Audi S3 mandates premium unleaded fuel, which typically costs more per gallon than regular gasoline. Conversely, the 2026 Cadillac CT4 only recommends premium, potentially allowing owners to save money by using a lower octane fuel grade while maintaining the shared 26 MPG combined rating.

The Cadillac CT4 is 9.8 inches longer overall (187.2 inches), which translates directly into 2.4 cubic feet more cargo capacity (10.7 cu ft vs 8.3 cu ft). While the Audi is shorter, their widths are nearly identical at 71.5 and 71.4 inches respectively.

Yes, the 91 hp differential, coupled with the S3's higher 295 lb-ft torque output, will result in significantly quicker acceleration times compared to the CT4. This 7-speed automated manual in the S3 is tuned for a more aggressive performance envelope than the CT4's 8-speed shiftable automatic.

For enthusiasts seeking balanced handling dynamics, RWD (CT4) is often preferred, whereas the S3’s AWD system offers superior traction in adverse weather conditions or during hard acceleration off the line.

The highway MPG ratings are closely matched, with the Audi S3 achieving 31 MPG and the Cadillac CT4 achieving 32 MPG. This indicates that despite the significant power difference, both vehicles are remarkably efficient cruisers on the highway.

The substantial $13,100 savings makes the CT4 an extreme value proposition, especially since it is only 6 MPG less efficient combined than the more expensive S3. A buyer could use those savings to upgrade components on the CT4 or cover years of fuel costs.