Had to chime in here. Bought a used race off of Gixxer_Kid over a year ago (wow has it been that long?)....
As he lives 2hrs from me, the drive home was pretttty obnoxious. I've had exhausts before but never one this loud. As I drive 6MT, I immediately realized it was not really possible to do 80 in 6th gear...
I could do 80 in 5th gear with minimal drone (applies anywhere from 68mph or more)
Or I could do 85 in 6th gear.
After looking back on that time now, my ears have adjusted to the point where the drone just doesn't bother me anymore. Sometimes if I am in the car for a very extended period, i'll sometimes focus on it and THEN it bothers me. But if I ignore it and stick to the correct gears, I find no problem.
This is such an awesome exhaust to use on the streets (vs. highway). The monstrous fury that is the low end burble when you hit the gas is intoxicating. Then as the sound blends into a higher pitch, you feel yourself coming back again and again for that progression as it's so unique.
While I am considering a switch to a (lesser droning) Akra Evo system, my purposes for doing so are strictly boredom. I could keep the Eisenmann on for the life of the car and would never look back.