This driver might have the best cooling DC has to offer, which I don't see any other than "standard" cooling on his other subs.
My point is, I don't see how it doesn't lose strength. Period. I don't care if its the best cooling they have. All I see if that the coil is open to ambient air, so it can only cool to what that is. I'm sure on a 100degree day, it doesn't take long to get the motor 150+ degrees therefore losing strength. But that's just how I see it.
I'm not saying the driver sucks. Just don't see it being a "great" daily sub. / of my story.