How will adding a new domain affect my blog?

I mean

**1** What about the links? Will viewers be redirected to the new blog address or I'll have to get a site redirect upgrade too?

**2** What about the rank? The google page rank of my blog is 3 now. If I add the domain will it be 0?

**3** Will about stat counter? Will wordpress count my stats as 0?

**4** What about transfer? Will I be able to transfer it to a new host in the future?(If wordpress made more stupid changes in the future) (If I add godaddy domain.)

I've read articles about it but these questions are confusing me. Your help will be appreciated. Thanks.

The blog I need help with is itspak.wordpress.com.