Dimples are not a problem
This TSB applies to 2007-2010 Mazdaspeed3, 2006-2007 Mazdaspeed6 and 2007-2010 Mazda CX-7 2.3L vehicles.
A small dimple may be found on the surface of a turbocharger blade. The dimple is machined by design and is not due to damage or poor manufacturing quality. The machined dimple is important to ensure rotational balance of the turbine and compressor wheels at high rpm.