Hello, I would like to replace the front standard loudspeakers of the standard performance audio system with a 2-way component system. I have the following questions: 1. Does the door panel provide space for a crossover, if yes which max. size ? 2. What impedance do the speaker outputs of the radio (2 or 4 ohms) have? 3. Does someone have a tip for a good 2-way system up to approx. 150 €?