Eisenmann race sounds amazing but is crazy loud. I think you should get the sport unless you're cool with being very loud at all times. I drove a E92 M3 with Eisenmann Race and an x pipe and it was louder than my E36 racecar with no muffler, no joke (but the E92 sounded so much better
).
FWIW my ears were literally ringing after 3 hours of highway driving with the ER and x pipe.