On Friday I finally went to Autocore to pick up my BMW wagon. It was in for a little bit of service, the ball joints were shot. While there Kyle was working on a S4 V8 motor. He was upgrading the timing chain tensioner from the plastic one above to the metal one installed on the engine (center of picture). The original bracket can crack over time which may lead to a slack chain and bent valves. But the cracks may not show up on a visual inspection. Kyle said this one broke apart after he pulled the bolts.