I recently bought a Reatta and brought it to a Buick dealer for servicing all those things no one but a Buick dealer can do. They seem to have mechanics with years of experience who know what they are doing, but be aware that it's not going to be cheap. This dealer seems reputable as they quoted me the need to replace one expensive part, but found out that wasn't the problem and replaced it with parts costing much less. I saved $100 on the part, but it took an extra hour to find the problem, so the labor made it a wash. Still, they did not try to soak me for a part I didn't need. If you want to know more, call me either at work 773-631-9290, or at home: 630-980-3823. Frank