Hi all, its being one year now since I have this 20017 e81 118i here in Poland and after facing and solving issues I would like to share my experiences and maybe help someone in the future saving time and money. When I bought the car it already had 127.000 km.
Keep in mind that I am not Polish and probably some of these issues would be solved faster if I've spoken polish better.
If you want the short version, you can skip the details and read the short version below the long version.

Long version:
When I bought this car it already had two known small issues: Rear view mirror was broken and hanging on the wires and the rear wiper was missing.

After riding for the first 4.000 km or so, I've had the first problem that would cost me significantly.
When starting the car one day, in a cold morning, it had difficulties starting and once it started it would stutter at idle and die, if I stop accelerating.
The first thing I could think of was spark plugs, an issue simple enough to solve. Since was living really close to a BMW dealership, I've taken the car there for checking.
They charged me 135 dollars for the initial diagnostics, what I thought it was a bit much but was prepared to pay for it, since it would mean a very good diagnostics from a specialist, right? I asked them to take a look on the rear view mirror, since I had bought another one and my key stopped locking and unlocking the car ever since.

After 2 days or so of investigations, I got the news that the problems were the Lambda Sensor (11787587130) and the sensor for low pressure (13537614317). The cost of changing it, including the man hours and the parts was somewhat around 1 thousand dollars. About the mirror problem, it was said to me a new mirror was required and the cost of it + install would be somewhat around 270 dollars.
I declined the mirror service and accepted the rest.
5 more days until the Lambda Sensor arrived from Germany. The day after that, the guy calls me and informs me that the mechanic broke the part when installing it and I should wait 5 more days.
After 12 days, I got the car. The vendor said to me that this was not everything, the spark plugs were also worn out but he installed temporary, already used ones as a gift ().
Not surprisingly, the issue came back after the used spark plugs were completely worn out. This time I bought them online and installed myself and the issue did not came back.
In the end, I will never know if the parts replaced at BMW were really necessary but that is life.


The second issue started around the next 7000 km mark.
Every time I would reach speeds over 140 km/h, the car would vibrate mildly. At first I thought it was because of the winter tires, so I didn't bother too much.
Gradually it would start vibrating with lower speeds, 130, 120. I changed the tires back to summer tires, did all geometry and balance since the issue was most likely there.
Unfortunately it did not solve my problem and after one more thousand kilometers, the car was vibrating even around 80 km/h.
After taking the car to two different shops, one mechanic found out the issue was a clearance on the driveshaft. This part replacement cost me around 900 dollars.
The last two issues I fixed were the ones I had when I bought the car, rear view mirror and missing rear wiper.


For the mirror, I bought an used one from a crashed e81 for 12 bucks. It is important to notice that I have tried a mirror from an e90 before and it did not worked.
The key is now locking and unlocking again remotely, so I have saved those 270 bucks a new one would cost me.
The rear wiper was not the only thing missing, the motor for the wiper was also missing. I bought this one online and it did the trick:
https://allegro.pl/silnik-silniczek-...582684700.html

Short version:

Issue 1: Engine failing to start and stuttering after start.
Solution: Had to change Lambda and Low Pressure sensors and spark plugs.

Issue 2: Car vibrating at high speeds initially, progressing to vibrating at lower speeds with time.
Solution: Had to change the driveshaft entirely.

Issue 3: Car not locking/unlocking remotely anymore after changing rear view mirror.
Solution: Bought an used mirror, this time from another E81. Installed and the lock mechanism is now back to work.