The ML system has a great sound. You have to hack the wires to enable use of dvd player and some phone functions whilst driving (you can use speed dials whilst driving). To enter destinations in sat nav whilst driving requires a more complicated wire hack or update to the new sat nav dvd which has input function enabled whilst in motion. I have posted a guide to hack the wires it's easy.
Test drive one first, they're not the best drivers cars. (Gear box has high ratios)