actually mr.jack i am serious, i dont own a WRX and furthermore Nitrous Oxide or “NOS” is not normally suitable for a diesel engine. Since diesel engines normally run lean (except when belching black smoke), adding more oxidizer isn’t going to accomplish anything. If the engine is over-fueled due to other modifications, then this might help power output … for a little while, until something breaks. being a diesel owner i would try looking for a propane injection setup, supposedly based on the chemical makeup of diesel fuel…Thus, propane is a better decision…