I would say it is just a 4.2L with an after-market exhaust. I would guess that within the next year, about a 1/4 of all of the R8's now in the country, will also have an after-market exhaust system. To many of us, they just sound too great, and give a significant boost to the car's HP. I am taking my car to Borla Exhaust soon for them to design their new exhaust for the R8. Many companies are doing this for the R8 because they know the potential with the 4.2L engine.