When it comes to the F30 3-series platform offered by BMW, the N20/N26 inline 4 cylinder engine is used in more models compared to the straight 6 option the N55. This means that the majority of people that drive the modern 3 series from BMW are stuck to the N20 2.0L turbocharged platform. The aftermarket parts for the N20 revolve around bringing the temperatures down and replace the plastic piping that comes from factory. However if one were to build signifant power to rival the N55, the turbo charger would need to upgraded, this poses a significant vulnerability in that the engine cannot take large amounts of boost pressure. Thus a engine build is required to strengthen the bottom end and improve the airflow dynamics of the top end.
This post showcases the build of the N20 engine that is completely rebuilt with forged internals, a port and polished head, and sleeved cylinders.