"using sealant your head gasket"に関する回答I think he is asking about a coolant additive. If so the answer is no. There are too many small passages and heater valves to clog. If your car is leaking coolant fix the leak, usually the temperature sensor in the lower radiator hose, water pump, or thermostat. If you have been driving it overheated the rigid coolant pipes under the intake are probably broken and you may have damaged the engine block by pulling the threads out of the head bolt holes.
"retrofit bluetooth to above model"に関する回答http://www.dension.com/products/car-multimedia-solutions/gateway-500 This is an aftermarket product that is superior to the factory system and a fraction of the price of a factory retrofit.
"Are the Break booster and vacuum pump the same thing?"に関する回答The N62 engine in your car does not produce any manifold vacuum. The brake booster operates off manifold vacuum. To remedy this the bank 1 (right side of the engine) has en externally mounted vacuum pump that is driven by the exhaust camshaft. The vacuum pump tends to leak oil from the front cover and BMW does not offer a seal for the repair. An oil filter o-ring from a 2007 3 series will work on the vacuum pump on your car. Any competent independent repair shop should be able to complete this for a fraction of the cost of a replacement pump. The entire repair at my shop is typically in the $250 range.