It is 2026 and RTR Vehicles just dropped a Mustang so ludicrous that Ford's own GTD might need a stiff drink. Meet the 2026 Mustang RTR Spec 5—a Whipple-supercharged, carbon-clad monster that cranks out over 870 horsepower and costs less than half of the $325,000 halo Mustang. If that doesn’t make you spit out your coffee, nothing will. RTR has been tweaking Mustangs since forever,...