I have an 08 and have driven a friends 2011. I have tracked mine a few times and tbh the e-diff works fine. You would be amazed the amount of performance cars that have e-diffs rather than mechanical diffs (I think the Ferrari F430 and 458's have e-diffs).
The diff wasn't worth the 5k difference in price at the time of purchasing my ISF (different between mine and my buddys). Preference would be a mechanical diff but beggars and choosers.
Although bluetooth music streaming and DAB.... I would like that but those are fairly easily obtained with relevant tweaking.