Sending a rod out of the block is probably stretching it, but detonation, absolutely, and damage to piston crowns and ringlands (sorry for the edit, auto-correct keeps saying England instead of ringlands!), especially with prolonged exposure to bad fuel, absolutely, though the ECU should detect detonation and regard timing/go into limp mode.
Yep, compressing air heats it up, which makes a hot day even worse, and combustion temperatures are a contributor to detonation.
You should look, otherwise you're making a decision that isn't as fully informed as it should be.
The US uses a different fuel octane rating system to many other countries (Australia included). While we (And Europe, and Japan) use RON (Research Octane Number), but that doesn't make their fuel lower quality (despite their rating numbers looking lower). The US uses PON (Pump Octane Number), which is the average of RON and MON (Motor Octane Number). Effectively, for the same fuel quality, they report a lower number - their 87PON fuel is roughly the same as our 91RON, their 94 is about the same as our 98.
American vs European fuels – Octane rating – eTuners
In Australia, our Stinger is factory rated for 91RON. Unless the factory tune is woeful or you get a terrible batch of fuel (the first is unlikely, the second not quite so unlikely), you're not going to see issues with running regular unleaded in a Stinger here in Australia, and you're unlikely to see significant (or even noticable) benefits from running 95RON or 98RON fuel (the reported benefits of better cleaning are hogwash) unless your car is specifically tuned for it. My current Liberty GT Spec.B is tuned for 98RON - if for some reason I can't get it, the fallback plan is to run a less aggressive map (I have three different maps, running on the SI Drive selector - I imagine the same can be done on a Stinger with the different drive modes - I will know soon enough).