They have serviced my BMW 335 for about four years. They are extremely knowledgeable and professional. I had a very intermittent engine problem when street driving. Then I took the car up to the Brainard Speedway an found it was a regular problem when going 100+ mph. I thought they had zero chance of finding it, but they isolated the problem, fixed it, and it has never come back. They are not cheap, but if you need care and feeding of high performance cars, this is the place to go.