I've performed everything imaginable and had various/multiple diagnosis done by dealer, indy, and Euro performance shop. I almost rear-ended someone so i decided to look into this further...What i discovered is that BMW issued a Service Bulletin (trany program) fix for 2004+ V8's but nothing for the 4.6iS. The only fix the dealer offered was to top off the trany fluid. They claim it's inherent to the performance engine

I stopped holding my breath, expecting them to do something about this.