My E-race exhaust arrived earlier this week after nearly a 6 week wait. I got it installed yesterday, and couldn't be happier with the sound. I regret having gone with the E-sport version on my previous M6, the race sounds sooooo much better, especially with the Eventuri cf intake! It's supposed to be only 6 decibels louder than the sport, but what I didn't realize before is that decibel levels are measured logarithmically, which makes the race almost twice as loud as the stock exhaust and the sport is only slightly louder than stock.
If you're planning to get an Eisenmann, you should act quickly because they will stop producing them for the E63/E64 very soon. They already phased out the sport version, only race can be ordered now from what I was told.