I am looking for some advice on the best way to solve this problem.

I currently have 3 partitions on my hard drive.
1) A fat32 partition where I have Windows XP installed (37 gigs)
2) A Linux swap partition (1 gig)
3) A Knoppix4.0.2 hard drive install on a ReiserFS partition (15 gig)

This system is using Grub as it's boot loader. Everything is working as it should. What I would like to do is create another partition where I could load either another Knoppix install that would be suitable for testing, or possibly another distribution of Linux, probably Debian.

The scenario, First I would create another ReiserFS partion for my next Linux install. I have over 20 gigs left on this box.

The Questions:
1) If I add another Knoppix install from cd to the new partion would my Grub boot loader file be correct or would I have to manually edit it?
2) Would it be better to copy or mirror my present Knoppix system to the new partition and go from there as a test version? What tools would work for this (i.e. Dd, Partimage, etc)? I am not very experienced with backup and restore in Linux (another reason for a test version). Again how would this effect my boot loader in Grub?
3) If I did add another distribution of Linux what issues would I expect to see?
4) Would any new linux install Knoppix or otherwise use my current swap partion by default?

I am probably being over cautious but I don't want to loose all my work that I put into this box in getting everything running smoothly.

Thank you in Advance,
Chip