I bought a AAA autoguard extended warranty for my 2007 335i soon after I purchased the car. It covers everything but wear items (including "luxury electronics", e.g. iDrive) for 7 years/100K miles. The cost of the warranty was $3000 and, at just over 72000 miles, it has paid out over $4500 in parts and labor. Most recently was new waste gates, water pump failure and the second time the oil filter housing has sprung a leak. I would not have an N54 out of warranty and have started window shopping via Internet. I truly love driving the car and regret that the F30 offers nothing of interest and at a high premium so I'm wishing the Japanese would produce a decent looking sport sedan.
2013 Audi A4 - Premium+/Sport/MMI/B+O Audio
2007 BMW E90 335i (retired)