The MBRP 4" Kit is a bit louder and more aggressive than the Heartthrob kit, though the Heartthrob system has considerably less drone at cruising speeds. The MBRP Black Series Kit also that protective black coating, while this version of the Heartthrob is just aluminized steel. The MBRP kit also comes with an exhaust tip and has arguably better fitment than the Heartthrob system.