Rechipping the ECU
The 200/400/600’s use a fully electronically controlled fuel injection pump (VP37). This means that the ECU controls how much fuel is injected. To alter the quantity and timing of the fuel injection you need to alter the chip on the ECU. To do this you need to unsolder the original one and fit an altered one. Not one for the faint hearted but if you’ve got a heavily modded car then it is worth considering. I’m working on my own chip at the moment although others are out there.