I hava a 2004 volvo s40 1.9 turbo. Does anyone know where i can het aftermarket performance parts to increase its performance? Also of anyone knows what all i can adjust or tune to get the most out of the oem parts i would really appreciate it.
Unfortunately, there are no custom fit performance air intake systems for your 2004 S40 with 1.9L engine, but you can try K&N panel filter. It will perfectly fit in your factory airbox and provide a better filtration and air flow. https://www.carid.com/2004-volvo-s40-air-intakes/