The turbos are screaming on the Ring. The 3.8 liter boxer motor has two turbos that provide more power than ever. The biturbo 3.8-liter, flat-six engine is expected to generate 650-700 hp and that will make the GT2 RS the most powerful 911 ever. Automotive Mike spotted the GT2 RS at the Nürburgring. So besides the looks of the car, we now also know how the car sounds.