Hi every Shi fu, I am driving a e92 335i year 2007I would like to ask what is the stock audio system for my babyAnd did anyone upgraded audio system as well, do give me some advice.I had ask in one accessories shops, the boss introduced me "prokick" tweeters to improve sound qualityAdd on with one amplifier with tile alignment to adjust. With price 1600 including installationAnd everything.Please advise me. Thanks and appreciate as I am someone who enjoy music in my beloved baby. Cheers!