To change to DSP you have to change the amplifier from non-DSP amp to a DSP-amp.
You also need to fit the subwoofer, and change the wiring on the amp. Wiring is different.
Once done, the new DSP amp then needs to be coded for your car.

Afterwards, you will be able to alter lots of parameters (echo, corrsover levels etc).
But some people are always dissatisfied with the level of hiss and echo that the DSP amp produces, they say non-DSP is better :-)