We have a simple approach when it comes to addressing the VANOS issues on S54 motor and that is to do it right the first time. Beisan (bee-san) Systems has figured out how to address the weak points of the VANOS, we use all of their products when rebuilding the VANOS unit, including the Exhaust hub and the Exhaust upper chain guide. We also use the updated BMW VANOS bolts as well as OEM gaskets and hardware. While we have the unit apart, it is thoroughly cleaned using our Ultrasonic cleaner.
This is a fairly involved job and it is important to have someone who understands the VANOS system the way we do to rebuild your unit. Too often we see people claim to have the VANOS done when in reality they only replaced the solenoid pack. Doing this complete rebuild ensures that you will not need to touch your VANOS for the next 80,000 plus miles.