I'm just a newbie, having gotten my CX2 for Christmas. However, it looks like you aren't a newbie so here's some thoughts.

I'm surprised you didn't pursue the TBE problem ASAP rather than waiting to crash, given you already have a 400. That might have kept you from having to replace other parts. Did you call tech support? I found them extremely helpful after my second or third crash rendered mine unflyable. And by the way, you can give them your phone number and they'll call you back so you don't have to wait on hold if you're the impatient type. I waited on hold and they kept you informed on your status periodically so I didn't mind.

You may have a "lemon", but if you didn't give tech support a chance before giving it major surgery, it's hard for them to help. Regardless, it sounds like the 3-in-1 might have gotten damaged during your crash(es), or it is just plain not good. Try calling tech support and see what they say you need to give them a chance to defend themselves before you flame them.

By the way, I was tempted to disassemble my outer shaft for easier access to replace my motors and found that the collar set screw was impossible to move. After having thought about it for a while, I'm convinced that they have applied Loktite to the set screw and I think the way out of the dillemma is to apply heat to the set screw with a soldering iron before attempting to loosen it. I'd be interested in hearing from others on how they have dealt with this issue. You did use loktite on your set screw when you reassembled, didn't you?

Hope you get your baby flying I'm having lots of fun with my CX2 and it's helping me learn orientation.

Mack