Engine Exhaust System problems of the 2004 BMW M3

Before I start explaining, I should mention that the car has been meticulously maintained with majority of the parts being genuine BMW. The chassis has 110,xxx miles at the moment, and the engine has 78,xxx miles. The engine had a failure in 2006 due to a rod bearing failure (recalled from BMW), and a remanufactured engine has been installed by BMW technicians at a BMW dealership service center in virginia. Recently my 2004 BMW M3 had a failure inside the engine that could have been very dangerous. On halloween night 2011, as I was leaving the gas station, I hear a very faint rattling noise up in the engine bay. I was contemplating rather I should take the car to the local dealership, or fix it myself. But prior to this, I've read many unsatisfying experiences people had at their local BMW dealerships. I worried that since this was a major problem that could be life threatening, I decided to do the work myself. I removed the valve cover, and noticed the exhaust side hub on of the BMW double vanos has failed. A mechanism designed to improve torque and fuel consumption. The hub had one of the 2 tabs completely broken off. Luckily the broken tab was still stuck inside the oil pump. If instead the broken piece came out of its location, and moved around in a engine this could cause a catastrophic failure. Ranging anywhere from approx $15,000 remanufactured engine replacement to possibly a high speed collision if the car was in motion during the failure. With a damaged engine, it is difficult to follow the minimum speed limit of 40 mph on the local freeway. The total replacement parts in my situation costs well over $3000 using BMW parts. Unfortunately, even with the current replacement parts from BMW, the problem would not be fixed since the currently new parts have just as much chance of failing as the old.