I think the headman are best for power from everything I have read. That being said I have TTI 1 7/8" on my W2 418 and they fit great, the passenger side one is super easy to install and almost requires two people because it will literally fall out after you install it. The drivers side is not easy, but once it is in it fits great. I just leave it in the car when I take the motor out and that takes all the pain out of it haha.