Of course the only common major mechanical failure SLSs experience would occur on a long distance road trip.
I was driving home from Wilmington, NC over the weekend when I hit 30k miles followed by a transmission “issue” light an hour later while cruising at around 70 when the car shuddered and dropped out of 7th gear into 6th. I pulled off to attempt to restart the car and see if just cycling the transmission would reset it. It didn’t. The odd gear clutch pack had apparently failed, leaving me 2nd, 4th, 6th, and reverse gears to get me home (6 hours away). To its credit, the SLS got me home on a half-broken (literally) transmission.
Based on posts from other owners on the official AMG forums, I’m one of three others that post there that also have experienced losing either half or all of the gears. I was lucky, if you lose the even gears, you lose reverse as well. The car is still under warranty for 3.5 years and 70k miles, which is a good thing, because a new SLS transmission costs over $20k and they aren’t dealer serviceable, so replacement is the only option when something goes wrong. The same transmission is used in the 488, F12, 650S, MP4-12C, etc. But they break more often and at lower miles thanks to more aggressive software in those cars.
Just waiting on a new transmission to show up. Luckily its fairly easy to replace with it being in the back, between the exhaust.