what should I consider before shifting to new custom domain

I'm actually planning to get a custom domain for my blog. However there are a few things I must consider before I do that.

Instead of paying extra money for a hosting plan, I'll continue to use Blogger's service to host all my contents but displaying my own custom domain. However, I'm not sure if this will affect my current Page Rank (PR). My PR is already very low and I don't want to start from 0 again.

I'm also not sure if the changes will affect my links especially in Technorati. I've just started using Technorati recently, so I think I'll be okay to rebuild my links again.

It's about time for me to use my own domain. My current blogspot url disallowed me from writing certain sponsored post. Besides I don't think there's a better way to spend my PayPerPost earning than a custom domain.