the Mercedes-AMG GT 63 S – actually packs 630 hp (470 kilowatts) from its 4.0-liter biturbo V8. Slotting underneath is the Mercedes-AMG GT 63, tuned to make a familiar 577 hp (430 Kw) from the same V8. Aside from delivering prolific power, both mills feature cylinder deactivation for increased efficiency while cruising.