I recently moved to New Hampshire and also own a 987 Cayman. I haven’t found a great shop yet, as my car has not needed anything except changing oil, but a few points:

1)Zaks Auto in Hudson was recommended by some, I went there for an oil change and they tried selling me a lot of things my car didn’t need, overpriced by 200-300%;

2)It’s a Cayman. It’s a fun car, and you want to take care of it, but don’t worry about the resale value. If you are not buying the newest one, you will likely pay $25,000-$45,000 and will sell it 30% cheaper in 5 years. So really you will pay $7,000-10,000 in depreciation for 5 years of fun. Overpriced service that could potentially make the resale value higher will cost just as much. Don’t use dealerships, find some good honest mechanic (and please tell me about him if you do!!)

Good luck!