This is not like the US A4.
The US A4 is below the 328i. This Dubai A4 is between the 328i and the 335i. The US S4 is above the 335i... You can't compare apple to apple between the Audi 4 and the BMW 3... They just don't stack up exactly.
Entering the S4 in this comparo would be biased the other way.
Anyway you can't just compare engines, there is so much more to it.