The Mazda RX8 was built by MAX Performance in Gorzów Wielkopolski, Poland. Under the hood sits a twin-turbo 3.1 L V6 built from a 3.0 L Saab B306 V6 and 3.2 L Opel Y32SE V6. Both engines are based on GM’s 54° V6 platform.
The engine features Hipeco ceramic-coated pistons, Re5pect forged rods, ported heads, 272 camshafts, Supertech duel valve springs, two Garrett GT2560R turbochargers, Tial 50 mm BOVs, Siemens Deka 850 cc injectors, and Bosch P65 coils. It produced 579 horsepower and 642 Nm of torque on low boost running off a Ecumaster EMU Black ECU. It shouldn’t be too hard to achieve their goal of 600+ horsepower.
They mated the V6 to a ZF 8HP70 eight-speed automatic transmission controlled by a BMW F10 shifter and a HTG Tuning transmission controller. Power is sent to the rear wheels via a Nissan 300ZX TT R320 rear end with 3.69 gears and Nissan 350Z axles and hubs.
Source: Racing Forum (build thread) via Piotr