Some questions about my new hermit crabs:)?

  Okay, I just bought two PP hermit crabs today. I have a couple questions. They're very active, always moving around and climbing all over, even during the day. Are they really stressed, or are they just really healthy? What should I name them? And also, do you think they will change their shells soon? They're both in painted shells, and I would rather them be in the natural shells I bought for them, because they are less hazardous. Thanks:)
that means they are healthy, they mite change soon, any name you want speedy rex mario?