Mazda RX-8 with an Audi 1.8T

The owner of this 2004 Mazda RX-8 spent three years of weekends and late nights rebuilding it from the ground up. The owner considering swapping a Honda K20 or K24 inline-four but settled on a turbocharged 1.8 L (AVJ) inline-four from an Audi A4 B6. The engine features Siemens Deka 630 cc injectors, Bosch Motronic ME 7.5 ECU, XSPower exhaust manifold, and K03RS6 turbocharger. The owner estimates the combination is good for 300 horsepower. Custom mounts place the engine further back which helped with weight balance but required some firewall trimming. He swapped the factory RX-8 six-speed to a five-speed model with an adapter plate and upgraded clutch. The car maintains stock suspension and brakes albeit resorted and/or rebuilt.

Source: RXKlub.pl (build thread) and SopelXL via Piotr