I think there's a balance here - sure, OEM coils for a particular car may not be as strong as aftermarket ones in terms of output, but remember the OEM ones are engineered to do their job for at least the length of the warranty (which can be quite long, in the case of an extended factory warranty). The aftermarket ones with a 90 day or one-year warranty only have to last 90 days to one-year. They can run at 100% 24/7, because who cares if they burn out 400 days into their life span? The stock ones are built to put out less than they are actually capable of, which is why the service life is so long. That's why, with every vehicle, finding "stronger" OEM coils from another vehicle is, to me, a better bet than buying aftermarket/third party coils. Finding out that the Afla Romeo coils fit the Fiat 500 Abarth perfectly was awesome - the magneti marelli coils were *so* much better than the stock fiat 500 coils. Swapped coils at 3000 ish miles on the new abarth and the stock coils were *already* starting to get intermittent.
I was mistaken above, btw - I still have my wife's Giulia coils in the garage, I bought stock Alfa 4c coils for my abarth, those are the exact same part.
Also the giulia was a piece of shit. Incredible to drive, but a piece of shit. Glad it's gone.