Below I have a few links to share.
First one is a Rain Sensing Wiper thread that may help. If the windshield was replaced, this may be part of the problem.
You WILL never know if there is a charging system problem. This is a "feature" of the E70, possibly only the N62 V8 engines?? You should consider a UltraGauge to monitor the charging system.
You should also consider getting on OBDII tool NOW before you need it.
You want the OBDFusion App and interface for $30 or less. Order the interface NOW! Trust me.
Android $3.99 App, interface around $12 for a total of about $16
http://www.amazon.com/Veepeak-Blueto...peak+bluetooth
iProducts $9.99 App, interface around $18 for a total of about $28
Amazon.com: Veepeak Mini WiFi OBD2 OBDII OBD II Scanner Scan Tool Adapter Check Engine Light Diagnostic Trouble Code Reader for iOS iPhone iPad and Android: Automotive
Water pump will leak and you will also want to install the Bimmerfix coolant stent.
http://www.xoutpost.com/bmw-sav-foru...dont-work.html
http://www.xoutpost.com/bmw-sav-foru...tem-issue.html
http://www.xoutpost.com/bmw-sav-foru...sfer-pipe.html
http://www.xoutpost.com/bmw-sav-foru...waterpump.html