If it was an RX8, I would already be thinking about a rebuild, an engine mount would be sagging, there would be bubbling sills, the coolant sensor warning would be permanently on, I'd be changing plugs and coils for the second time and I would be spending 50% more on fuel. It's a much better mannered car so far and the Toyota spares are a bit cheaper.
I don't believe it's that unusual for car club enthusiasts to see a few engine failures, as they ask the most from their cars and make "improvements". My cause for concern is that there are fewer '86s on the roads than there were RX8s. That might play positively or negatively in future.