Hey guys, I purchased a 2009 BMW xDrive48i with only 51k miles on August 29th (exactly a month from now) and the dealer gave me 3 months warranty. The very next day my iDrive system tells me I have low oil pressure, so I searched online and a lot of people said its just a sensor that has to be replaced. I took it back to the dealer and they fixed the issue. My inspection sticker had expired but DMV won't inspect a vehicle with temporary plates so I waited until the dealer gave me my plates on September 19th. The following day I took it for inspection and the truck failed for visible smoke

the inspector showed me that if I idle for about two minutes and floor the gas peddle white smoke came out the exhaust. I called the dealer and told them what happened, they said bring it in and they would fix the problem.
I brought the vehicle in on the 27th and explained what happened in DMV. Yesterday they called me and told me they fixed the issue so I happily went to pick up my car. When I arrive the truck had a new inspection sticker and the advisor said it was just low on oil. So all they did was topped her off and inspected the vehicle. I told him no, oil level was not the issue since I could see the smoke from the exhaust.
So I asked about extended warranty and he said because of the year they could't provide extended warranty but I should look into 3rd party warranties and make sure gasket and seals are covered. I found this strange that he mentioned thise specific components so I did a little searching and found out the n62 engines are famous for valve seals problems.
My question is, what should I do now? Record the smoke coming out of the exhaust and bring it back in until they decide to actually do the work? I am not going to spend $8,000 to fix this problem after my warranty expires. Any suggestion would be appreciated.