I've already had my engine destroyed by this problem. Fortunately, they replaced it for free, and fixed the intake. That was many months ago, and I got the recall notice today.
What gets me is that the recall frames it as an emissions problem. The bad emissions are a result of an engine that's been wrecked. Sneaky laywers...by not directly mentioning the internal damage that the screws cause, then more people will settle for just having a piston or two replaced.
Just make sure that your dealership has a boroscope and can inspect the engine internals firsthand. The first place I went to didn't, and wasn't able to diagnose the engine, only able to fix the butterfly so I could hobble home to my regular dealership.
Kodus to Mazda for replacing my engine before the official recall, unlike Subaru who refused to acknowlege the wheel bearing failures on the 98 Impreza series that caused me to get rid of the car.