Geeklog Forums

I have a few questions about Geeklog and am hoping someone can help me out. I have become dissatisfied with PHPNuke and am looking to replace it. Here are my questions:

1. PHPNuke has an issue regarding the number of requests it makes to the MySQL DB, and my web host place some kind of limit on that number. Here recently I have had more frequent site crashes because of this. I have found some work-arounds, but they're only temporary. Does Geeklog place this same burden on the DB?

2. I use the built in (and heavily modded) phpbb forums in nuke. Now, looking at the forums on Geeklog, they seem very similar to phpbb. If it is phpbb, are they modded to the extent that they are on phpnuke? Also, is there a way I can copy the forum posts from my phpnuke forums to Geeklog forums?

3. Security seems to be a major concern for all websites, but especially phpnuke sites. How does Geeklog compare?

Thank you in advance for your help with these questions. In the meantime, I intend on installing Geeklog on my server to see how it works and if it will fit my needs.