Ok, new plan. Decided that since the bottom end is still good, I'm going to keep it, and just do cylinder head gasket set and refinish the stock heads while I'm in the process. I also will most likely get a new oil cooler, and a road race oil pan while I'm in the process of doing all this. I'll post more details once things start moving.

My 335 is running 250 on the streets (oil temps) with an oil cooler.

Is this a problem?

Exteneded OCI's are fine if you are running on the highway 95% of the time.

According to who/what? That may be true for 95% of the cars out there when running a decent oil, but not the N54/N55 equipped BMWs. Even Mobil 1 0w-40 has been destroyed in as little as 1k miles of average driving with these motors. They throw out far too much heat/fuel dilution to run safe at the factory recommended 15k mile OCI.

Maybe if you were running a biosyn like RLI, etc. I'd feel safe coming close to maybe 10k, but not until multiple UOAs were done to make sure everything was still in check.

There is something wrong if you are destroying a Group IV PAO Full syn in a thousand miles or less. Are those engines that shitty?

I have customers running BMW5w30, M1 0w40 all with the same effect, the wear control is good if we change the oil at 1000 mile intervals but the deposit formation from REAL volatility issues are slowly damaging the engines. I just worked a 07 335 Biturbo yesterday USING ASTM lab tests on the used oil and M1 0w40 went from VOA flash of 430+F to 240 F in 1150 miles, oil sheared to 12.1 cSt and fuel was at 1.99% by IR. Amsoil has not been tested in this engine yet. Because Amsoil is a traditional based PAO I predict similar results to the M1 0w40 which is still one of few M1 products that can perform reasonably well.

RLI BIOSYN is the only oil I am seeing work well in DI RS4 or 2.0 Audi or the BMW bi turbo 3.0 I6 in the 335I. They both are killing every oil I used to recommend. I am not kidding and have no interest in promoting one oil over the other.

reb03, the M1 0w40 should not be run longer than 1000 miles to be safe.. Audi and BMW know they are having problems but are marketing tied to certain LARGE oil company that sponsors BITOG thus they cannot speak out about it.

GC 0w30 green might work well here but the fuels chemistries have changed so much that it may be out of date to protect as well as I would want to see.

According to who/what? That may be true for 95% of the cars out there when running a decent oil, but not the N54/N55 equipped BMWs. Even Mobil 1 0w-40 has been destroyed in as little as 1k miles of average driving with these motors. They throw out far too much heat/fuel dilution to run safe at the factory recommended 15k mile OCI.

Can somebody answer me this? Why is DI harder on the oil?

Yes, but how is fuel getting into the oil? Also why is it not burning off like regular EFI cars? Are the mazda DI cars having similar issues? DI is supposed to increase efficiency, which tells me that it atomizes the fuel better, which should reduce dilution.