To add, On a stock setup it isnt that big of a deal, Especially if you havent upped the spark plug gap. But as you start making alot more boost and dumping in more and more fuel, a hotter bigger spark does make a difference. Look at the 03 cobra world and them blowing out spark at higher rpms. They just dont understand that you need to up the spark amplitude instead of moving it to a 20 or less gap to keep it from blowing out...
Our coils are just fine and do more than enough job making our hp levels. The others are a waste. They also dont last very long, and seems anytime i see them here on cars, there is a spark problem and they end up putting stock ones back on.