2007 BMW 335xi - Purchased the car in 2012 at approx 36,000 - car currently has 66,900 miles

Started car one morning and it was idling very roughly, backed out of driveway and yellow half engine check light came on. Called dealership due to concern with driving 30 miles to bring it in for service, had it towed. Received a call that it needed new spark plugs, new pressure converters, and possibly new fuel injectors. Keeler BMW of Latham, NY could not confirm what the exact problem was. Picked up the car, drove home - no engine power at all, no turbo, rough idle, and barely could make it over 50mph. Was told by dealership that Cylinder #4 was misfiring and the only diagnostic code that was coming up was p0304. Spark plugs were previously replaced at approx 41,000 miles by dealership, and plugs 4,5,6 were very dark after only 20K miles.

Did my own work to the vehicle and replaced all six spark plugs, and two pressure converters. Did not solve problem. Also tried replacing coil packs did not solve the problem. Researched online and found SO MANY issues with the N54 Engine Model. The following bulletins pertain to these types of issues: SI B13 03 09 and SI B13 14 10.

Specifically stated in the bulletin ending in 10 was information about faulty fuel injectors with the part numbers beginning with 13 53 7 537 317-xx or 13 53 7 565 138-01 up to 7 565 138-07 must be removed and marked with the cylinder number. I checked my fuel injectors and they were all indexed under 13 53 7 565 138-01. I contacted the dealership again and was told that my vehicle, according to the VIN, had an engine production date of March 2007, and this recall/bulletin refers to models that were made April 2007 and forward. ONE MONTH of a difference. My issue is that I would have paid $1,000 to the dealership to do the work above, and that still would have not solved the issue. But, if I take the car in now, they are still not going to be able to tell me exactly what is wrong with the vehicle but will continue to replace parts until it runs when clearly there are many recalls, extended warranties, and lawsuits that revolve around N54 - E90.

I find it VERY HARD to believe that my car is having the same issues as all of the other complaints I have read about turbo boosters, fuel injectors, lack of power, check engine light, misfiring, loud rattling, and shaky idling just to name a few. I contacted BMW corporate and they were of no assistance and referred me back to the dealership and said there is nothing than assist with.