The first item I ordered off of DSM Parts was a Defi D-series boost gauge (which BTW, is a work of art). I was very excited to get this gauge and anticipated its arrival. When it got to me, I opened the case and was saddened to see that the needle was sitting off center (about 3psi off of 0).
Less than happy, I immediately called DSM Parts and spoke with a gentleman about the problem. He informed me that the Defi gauges have had similar past problems due to rough shipment which causes the gear teeth to jump, causing the needle to sit off center. Before I could say anything, the gentleman told me that arrangements will be made via UPS to pick up the old gauge, as well as send me a new gauge (which was all taken care of in less than a week). Better yet, this was without any more money out of my pocket. This proves that these guys really do care about customer satisfaction, even if they have to come out of pocket to make things right.
Since then, I have ordered numerous parts from DSM Parts and will continue to do so. The customer service level and product knowledge alone is well worth it!