I think the OP needs to define the term "fast". Does he want to be fast around a road course track? Does he want to be fast strictly in a straight line? Does he want to brag to his friends that he has the most horsepower? Theres lots of different cars for each situation. Its pretty simple, want the fastest "stock" cars money can buy around a track? Get a Senna, P1, SVJ, Performante, 918, or 720. You want something that no car can touch from a roll or runway racing? Get an Underground Racing Huracan end of story. Want something that is stock and great at all these things? Get a 720, 600lt, or 570. The OP stated that he wanted to beat his brother, and I'm guessing just in shear horsepower numbers and straight line speed is what he means by this. So why not just buy a challenger hellcat for $50k, spend $5-10k and throw a bigger blower, tune, and drag slicks on there, and crank out 1000 hp+. You'd save a heck of a lot more money and have a lot of hp for the money $$.