I'm experiencing the same issues with my 2004 735i and have been pulling my hair out trying to get an answer. Realoem have my car listed as an N62. Great to find some like minded people ,as BMW keep saying nothing in fault but I know that it fairly quickly developed drastically reduced low end torque and a unresponsive tranny (the automotive type) which I previously thought was unrelated . Thanks for the insights and I'll Keep watching this post and contributing with any more info I can discover.
P.S.Is an "indy" a non dealership mechanic. Sorry for the dumb question but I am an Aussie.
Thanks from dirtdad