Similar to
siwo for me. Purchased new in 2016 and have low milage (12k miles).
Issues:
1. Minor infortainment issue after purchase. Dealer updated the software and no issues since.
2. Exhaust fixing bow rattle. This is likely due to the new aftermarket exhaust I had installed recently. It only rattles once a month, at certain ambient temperatures, so I haven't bothered changing the $8 part.
Let me know if you want the N55 service manual the BMW techs use. IIRC it has labour times for most maintenance items and engine diagrams etc.
Based on previous experience, once a BMW hits 6-7 years things start getting expensive so I think we are good till 2022/3.
Also see this ranking:
https://www.jdpower.com/cars/ratings...s-convertibles