The concept of accelerating from zero to 62mph in less than four seconds takes a bit of bending your head around, but that's the capability on offer from Audi's latest RS6. There's now the option of a 'performance' version with output boosted by 45PS to 605PS, but even if you go for the standard model, you're looking at a top speed of up to 189mph. That's coupled with potential for this leviathon to deliver up to 29.4mpg. Overkill doesn't come any more polished than this.