The new JLT tube is 4 1/4″ ID, rotor molded plastic to resist engine heat and keep the intake air charge nice and cool. NO METAL TUBING HERE!!The tube has a smooth taper to the throttle body which increases air speed and horsepower.GAINS5.7 testing showed 10-15 RWHP & 10-15 RWTQ are typical with this kit.6.1 testing showed 15-20 RWHP & 15-20 RWTQ are typical with this kit. FINISH OPTIONSStandard finish is an OEM looking black textured plastic and also available in your cars exact body color. All painted tubes go through an in-depth process to remove all the texture, then we use only the best quality materials to give each tube a smooth gloss finish.FITS2005-13 5.7 L Charger, Challenger, 300C & Magnum.2005-10 6.1 L SRT8 Charger, Challenger, 300C & Magnum.