A lot of LI Alfisti use Alfa Clinic on the South Shore. I also live in Huntington. Based on a fellow Alfa Owners Club member recommendation, I have started to use International Auto Repairs on East Main Street. Angelo is the owner. They are not the cheapest shop, but I believe he is honest and thorough. He is not the first shop I have used (I won't mention names), but I found his work superior. He deals with a lot of high end cars - Ferraris seem to be regulars in his shop. He also is well acquainted with Alfas and their "issues".
Ben - I live in Center port - Angelo at International Auto all the way. Aside from knowing Alfa's very well - he is honest and very capable. Thumbs up to Angelo!! By the way - I've spared no expense mechanically on my Quad and Angelo has talked me out of a lot of work I thought should be done but he felt was either not necessary or overkill.
Alfa Auto Clinic in Baldwin has always been good to me.
I've taken all of my cars there at one point. They really love Italian cars and have a parts room that is stunning. The place looks like a dump but they know what they are doing and are very honest and experienced.