I put one in a friend's frame last year. It is slightly tricky to fit. I don't think it could move once it's in (it is impossible to remove without a special FSA tool, and even then the frame could be wrecked; carbon frames often have an alloy sleeve and this could push out of the frame before the adaptor pushes out of the sleeve).
You need a headset press and you need to be careful it goes in straight. This is the difficult bit as only about 1cm at the front of the adaptor touches the shell, so it's a bit like pushing spaghetti. DO NOT APPLY THE THREADLOCK UNTIL THE SECOND FLARED SECTION IS ABOUT TO ENTER THE FRAME! The instructions don't specify this but we decided it would be prudent, and we were right...it was sufficiently hard to get it in straight that we left it overnight and tried again the next day (standard mechanic's technique when defeated by something!). Couldn't have done that with threadlock on it - we'd have been truly stuffed.
I was thinking of buying a Cannondale CAADX a few months back, and read in a few places that this adaptor didn't work with their BB. Something to do with the derailleur cable being run through a groove into the centre section of the BB so the wider section of the adaptor couldn't pass over it.
I have a wheelsmfg shimano fit already, started creaking last year put new bearings in with loctite still did it, and then loctited the crank to the bearings and now happening again im just wandering if the wheelsmfg BB is moving between itself and the carbon, been a right headache, which is why im asking about the longevity of the above BB adapter.
I used one on my CAAD10 road bike, and another on my Worx CX bike. They both worked perfectly.
You need the right tools to fit them, I made up something like a headset press with some alum spacers and 12mm studding. I also used some low strength loctite, belt and braces. Effectively converts the frame to a threaded BB shell. On both bikes I then fitted SRAM GXP BB and cranks. No creaks. Perfect. Getting Them out again needs the right tools, but is very doable.
As mentioned above, not suitable for every frame, as sometimes the bb cable guide mounting screw may foul the adaptor. Internal cabling may also be an issue.
I definitely wouldn’t use on a carbon frame, there are better solutions for that, look at Wheels Manufacturing, Praxis and others.