im not sure the Monster GT pipe will make a diff. It is alot bigger than the stock pipe so im not sure if it will fit the evader. The evader pipe is one of the very few 18 pipes out there and i think it works great. And the power of the engine dosnt make the better truck. U need to be able to control the power and the TZ18 has a tonne of power. Also im not sure that that header will work. IF my memory serves me right the RS4s engine faces to the front of the car and the evaders engine faces to the side. So your pipe will be sitting on the tranny case or over the fuel tank with that manifold.