I have a 2009 E93... long story short: Had a water leak that damaged the AMP. Fixed the leak and now have to replace the AMP. Should I go OEM replacement or aftermarket replacement? Have the Pro head unit and the E93 is setup for bluetooth phone integration, etc. but not so equipped from the factory. Would like better iPhone integration both phone and music streaming. What to do? Replace the OEM AMP as is? Replace with a OEM AMP that supports the iPhone integration objectives (is that possible)? Replace the AMP with a aftermarket AMP that meet the iPhone objectives (again is that possible)? Replace head unit and AMP with aftermarket products to meet objectives? Thanks for any advice.