Hmmmm, In Portsmouth I think I am only familiar with some of the mom and pop places that have been around forever. Namely I think of 'Big Al's' on Airline (Next to Moseberth's Chicken) Although I have never been there personally, I would say that their longevity in the same spot says at least something.
I have a buddy of mine who owns his own shop, so normally I do my research first then bring it to him with a basket full of parts.
Good luck!
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