While these spy shots give us a more accurate picture of what to expect from the M3-rivalling Audi super-coupe visually, there remains much debate and speculation over what will be providing the motivation. The same 4.2-liter V8 from the RS4 remains one solid possibility, with the potential for a power increase to 450 hp. Other reports suggest that, like Audi differentiated the RS6 from the S6, the RS5's V8 could gain a set of turbochargers. Meanwhile, a third possibility involves shoehorning in the V10 from the RS6, with or without the turbos. Which option makes most sense depends on how Audi views the positioning of the RS5: a two-door RS4, or two-door RS6, or a beefed up S5. They all make sense to us and we'll have to wait and see what turns up. Either way, we have a feeling we won't be disappointed.