Hi all masters, I have short listed a BMW 318i, Japan Specs. Pls help as, 1. It does not come with CD Changer but Navigator with Business MD. Will it be easy for me to purchase a third party CD Changer, install on top of the navigator unit located at the chasis inside the car boot? Or i have to look for the ori one, and how much does it cost?2. Radio frequency up to 90 only. What should i do? Is there any preseting i could configure?