Our GT350 and GT350R 5" splitter kit was wind tunnel tested and with the factory GT350 under tray produced around 125-150 lbs of extra downforce at 100mph and over 300lbs at 150mph depending on the set angle. You can also add our side plate setup to further produce another 50lbs at 100 mph as well as add a set of our canards. Adding our canards increased front downforce even more. This splitter must be balanced out with a wing. Our Apex 8 or Fulcrum 14 will be good matches. The splitter comes with brackets, splitter rods, and all hardware to install.