Matt, let me make a suggestion. Build your plane to fly, not to crash. If the crash is severe enough to damage the rx a little extra foam isnt going to help. Many times rx damage in a crash comes from the servos being snatched out of the rx and not from the impact of the rx.

If a crash is immenent with the tower 51 you might need to sharpen your skills a bit more with a trainer.

The main purpose of a micro rx is to save weight. If you have one lying around its no problem to use it, but I wouldnt recommend buying one so you can wrap it in more foam.