If you do not need the space of a sedan, you should decide on what car you like better when driving. It sounds like you have fallen for the Cayman, so go with it.
That being said, my new 911 has been a problem for me. I had my old 997 for 6 years and it was not in the shop one time except for routine maintenance. However, my 991 has been in the shop for 2 months out of the 5 months that I have owned it. While my dealer is great, dealing with Porsche NA has been a nightmare. I even spoke with the head of Porsche NA, who expressed his frustration with the lack of communication from Porsche AG. I am not sure if it is because of the recent takeover by Volkswagen, but the company has definitely changed. I still love their cars, but the company is totally awful. On the other hand, my experience with BMW has been the opposite, BMW values their customers more than any other car company. You truly are one of the team when you buy a BMW, which cannot be said for Porsche.