Does changing domain name affect google search engine traffic

I have a blog hosted at blogspot. If I change it to custom domain, a permanent redirect will be added at my .blogspot address.

So my question is whether my Google traffic rankings change a lot? Some say yes some say not much. I get 90% of traffic through Google.

And how long will it take to recover the traffic.

Also, there is another blog which is copying mystuff. So if I change the address, will my blog be facing problems of result filtering in Google search results?

 

yes it will affect the traffic and your index pages.

 

I do not think a simple redirect can preserve all of you traffic and rankings...