Backing up HDD and Xbox Live

[Jago]

I'm new to the scene and I had a few questions. I'm planning to get a Matrix Mod chip. Answers are greatly appreciated.

1. Will using Evox on my Xbox have a conflict with Xbox Live? If so, is there any way to prevent a conflict?

2. Is there any specific brand DVD-R/+R that works best with Xbox?

3. Before I log onto XBox Live should I physically remove the Matrix chip or can I simply reflash the bios?