Tell him you have an original Skyline motor in your car. Just be sure to use the word "R" and some numbers behind it when you tell him what kind of motor it is (e.g., "I've got an R32 swap - original Skyline motor right here, bro").
He'll be like, "Oh, yeah, so - this muthafucka right here is GODZILLA. I ain't skeerd." Then proceed to tell him - with a noticeable smirk - that it's apparent he didn't hear of "Operation Kazanishi" (or Operation whatever - just make sure the name sounds Japanese). Then you tell him about how "Kazanishi" (or whatever made up Japanese sounding word you just said) is Japanese for "respecting ancestry." He will give you a confused look. Then you can tell him that Nissan knew that the new GT-R would be unbeatable, but didn't want to tarnish the names and reputations of their ancestors, so they decided to equip all GT-R's with a specialized "chip" that "senses" when any prior model Skyline engine is near and automatically cuts the GT-R's horsepower, torque, boost, and so forth. This, according to the tech wizzes at Nissan, would forever insure that the GT-R would never humilate its predecessors.
18 year olds believe anything if you say it with enough confidence.