What is the fine-grained topic of the following text: GT Superbike 2 Estimated value: $25,000 Frame: Carbon fiber Fork: Steel with composite wrap Headset: Custom bushings Stem: Custom composite integrated Handlebars: Custom composite integrated base bar with aluminum aero bars Cog: Alloy, 15t Chain: KMC Crankset: Mavic custom, 55t, 172.5mm Bottom bracket: Custom extra narrow square taper Wheels: Mavic custom carbon tubular Tires: Continental Tempo, 19mm Saddle: San Marco Strada Hi-Pro Seatpost: Integrated Weight: 18 lb., 10 oz. Only return the topic.
GT Superbike 2 Specifications