The dual tail motors cut current load making the motors run cooler as you know the stock single motor gets very hot, another reason is if one motor dies on you, you have a back up to get you down safely. Lots of people are using the dual tail motors and I have read a lot at different forums and no one I have heard of has had problems due to the dual tail motors. Fuses are good the auto fuses may or may not be fast enough but sometimes they are faster than you. I know they have saved my 4n1. As for the cnc head I like it because it does not break less time fixing more time flying, Also looks good. Plastic blades may be a little more dangerous but they will save you a ton of money. The tail fin I believe is a little longer than the stock stick and much stronger (looks good too) also that little stick is very difficult to get out of their, if you need to change booms or it breaks off. The tail fin in the pic clamps on as well as the dual tail motor mount in pic in fact the tail fin is made to bolt right onto the dual tail mount to save a little weight but it comes with its own clamp if you are not using the dm mount. Both of these upgrades make changing the boom very easy, as said before less time fixing more time flying. As for the dd tail not to familiar with it as I am running the Duals.