Based on the success of the R8 race version Audi created the Audi R8 GT. It's 100 kg lighter then its sisters, but the v10 engine gained 40 hp. With almost 200'000 Euros it's quite expensive, but comes fully equipped with what you may need. You can even order a race version with a four point harnesses, roll cage, fire extinguisher and cut off switch.
It clearly proves that you can make this car lighter. Now, coming back to earlier posts, let's take that lesson, but replace the heavier V10 with a light V6, get rid of the 4 wheel drive system and we would have a really exciting car that probably could almost match the performance of its sister cars. But as we can see, for the time being Audi goes the other way by adding exclusivity and horse power.