So I just installed an Eisenmann Sport exhaust on my 335i. I was told that this was the recommended version for car because of my bi-turbo engine-- that is, get the Sport versus the Race to avoid annoying drone.
Unfortunately I dropped over $2k on it, waited for months and months, finally got it on and I'm just not super stoked.
I've been driving it all morning and it's at most, 10% - 15% louder than stock. I swear on my life, most of the time, it's totally dead silent at normal speeds. I mean, there's no drone, of course. But there's not much of ... anything... really.
Even the exhaust shop guys were dumbfounded. One of them yelled, "hey! did you just put the stock BACK on??" While I was revving it up in the shop.
Maybe I'm spoiled? My last two cars were S4s that had amazingly ballsy V8s up front. When you dropped $900 on an exhaust for it, people drooled when you drove by.
I'm gonna see about returning this thing and getting a different unit. (fingers crossed). Julius??
So a word of caution to you all, the Eisenmann Sport IS NOT for you if you're looking for loud. If you're looking for a slightly different sound than stock -- or want something even slightly quieter than stock, then this IS the system for you.