There are mixed opinions on the forums and at the mechanics I've spoken to about aftermarket sensor. I've replaced both throttle position sensor and crankshaft position sensor with Goldwagen ones (not sure about the brand) and a couple of days later the codes showed again. I would rather buy from Bosch or Diesel Electric (think they also stock Bosch) but would need to do some further reading about Bosch/Siemens compatibility. Hopefully some of the good mechs on the forum would share their experience.