I got Nonnef's replacement antennae today and just replaced Hasbro's rubber garbage. I knew the soft rubber was bad, but it wasn't until I made the swap that I realized just how bad Hasbro's original part is. fakebusker83 copied the part almost exactly if you'd like to see a picture. The antennae are actually one piece, but I did not believe it until I saw it with my own eyes because they move separately. Over time, play, or just occasional transformation I have no doubt part will tear internally at some point, and eventually either fall out or rip off.
Nonnef's replacement parts are two separate pieces, and that was definitely the right decision. There is a minor clearance issue with the replacement parts, but with a little practice it's barely noticeable, and I'm not worried about anything breaking. They look great and stand straight. I would not recommend pulling on them to get the head out of the torso, instead either use a screwdriver to pop it open (a big failing by Hasbro engineers) or, as I have found, pull Silverbolt's head assembly forward enough to get a finger into the cavity in order to pop Superion's head assembly out of the torso.
I give Nonnef's product two thumbs up.