Interesting - they must have altered the design for more powerful engine.
Just seen the S4 is getting a 3.0TFSI SC unit, although you should only buy the S-tronic version as its 224 on co2, the manual is 229 so hits the high tax band.
That logic won't really stand up. Tick a few options boxes on ether auto or manual, and the extra weight, particularly from stuff like sunroofs, rear side airbags, or security glazing, will push it into another co2 bracket anyway!
The supercharged V6 does sound interesting though . . . .