I ran the Actinium in 17.5 and 13.5 at IIC, and this is the first time there where I didn't feel like I was chasing motor trying to keep up with the other guys. I had other issues, but motor certainly wasn't one of them.
I had to brake on the straight (twice) in the middle and again at the end on several occasions in 13.5 because I ran down the guy in front of me. These motors are legit. I wish I could get back all the money I spent on D4's that are now paperweights.