Sorry to tell you, the Mayo will never go away. Water vapor is a by product of combustion and the crankcase is drawing outside air with moisture in constantly.
Mayo is NOT a BMW specific feature or option, albeit a "standard" feature or option.
A few main factors impact the Mayo:
1. Engine coolant temperature, I estimate that about 30% of the vehicles on the road have soft thermostats and do operate at the proper operating temperature.
2. Large oil sump takes a 3-4 times longer to come up to temperature than the engine temperature. Short drives are NOT good when you have a large oil sump.
3. Contaminated oil. Moisture caught in the crankcase or oil that has not been "cooked" out. I always start off the Fall season with fresh oil in all my vehicles regardless of mileage, however, I specifically have timed my oil changes for the Fall and for the most part this falls in line with my driving style.
4. Crankcase seals and CCV that is degraded. Cracked or leaking CCV hoses, leaking valve cover gasket, cracked valve cover, leaking oil fill cap and leaking dipstick and dipstick tube O-rings. I suggest a proactive replacement of the CCV system by the vehicles 8th birthday. The parts may last longer, however, it is not if, but when the CCV and hose, valve cover gasket and other things need to be replaced. If you wait, like anything you will end up having to do "emergency/non scheduled" repairs usually in the Fall or Winter. Plan your repairs, you can control the cost and schedule.
Another major part of Mayo is MANAGEMENT.
Suggest read read these links -
Bit worried about mayonaise... - E46Fanatics
Check your thermostat/engine temp - Report In - E46Fanatics
I have covered ALL things M54 in great detail on other forums with thousands and thousands of views and help many forum members resolve problems like this.
Enjoy your E53, but plan on a fair amount of PM to keep the vehicle reliable.
Fuel pumps, intake air path and vacuum leak problems, valve cover can OFHG, cooling system are all key areas to focus on.