New to site, been thinking about picking up a used 2014 M6 convertible or a 2014 or 2015 650i with low miles, which interestingly enough seem to be around the same price.

My concern is with reliability on these models. I read many issues with earlier 2012-2013 models and entire engine swaps needed which is scary. Do the model years mentioned above in either the M6 or 650i suffer the same fate?

Also, what extended warranty company do you all recommend for these types of cars and one that will stand behind it - or is bmw extended warranty the only recourse?

Appreciate the assistance.