I was going to go with this solution but don't think I need it. I track the car for 4-6 weekends per year. With my s/c kit and the twinscrew's low end torque, I really don't need to hang above 6k rpm too much. In fact, I think my car does best between 3.5k rpm to 6k rpm.
I've concluded from past threads, the Greg Smith solution is the only way to go if you're going to go through the time and expense to do this.
2013 F30 328i - Melbourne Red
2011 E90 M3 - Monte Carlo Blue
2004 E46 M3 - Imola red