questions from new blackberry user

Hello!
I got my new Blackberry Bold last week. I am very pleased. But i have a few things to resolve. I would be glad, if i can find my answers here. Here are my questions:

1. I took my Blackberry from Vodafone without connection. (with a special deal). Since i bought it without connection, i was able to get the unlock code from Vodafone. My device is unlocked now and i want to use it with an Orange sim card. Of course blackberry has a software for Vodafone on it. Should i update it with the one for Orange? (I found a newer version on Blackberry site for Orange.)
2. I hope that my Blackberry will not be locked again for Orange, if i update the software with the version for Orange. Am i right?
3. Is there any significant difference between the versions for different operators? Will i loose something if i update to Orange version?
4. I cannot use Blackberry Maps application, because my operator doesn't support it. But i need a good application for navigation, because i travel often. I heard that i can use third party map applications with the gps of Blackberry Bold. Which application should i use?

Thanks in advance

1) Yes. It is always preferable to have your carrier OS
2) No worries. Once it is unlocked it is unlocked forever. Updating
the OS will not change that.
3) No
4) Nav4All - Free gps navigation for your mobile phone!