back up to increase partition size

[Constantinos Maltezos]

This may not be the ideal list to post to for this, but I'd like to try anyway 
as I find you all a friendly and generally very helpful group.

When I installed Kubuntu on my laptop, I shrank my Windows partition to leave 
10 gigs of space for it (the harddrive is 100 gigs).  I now realize how much 
of a mistake that was (especially since I haven't logged on to Windows since 
Kubuntu's been installed) and would like to give it a 20 gig partition.  Tell 
me if the following plan is the best way:

Tar my current installation of Kubuntu onto my Windows partition (it has 38.5 
gigs free and Kubuntu is currently taking up 8.5).  Then use my gparted live 
CD to delete the current partition and create 20 gig one.  Reinstall Kubuntu 
from the CD, then untar my old one back onto the new partition.

My main questions, if this is indeed the best way of doing it, are if tar will 
keep all permissions, owners and groups intact and what would be the best 
switches when I tar it?  Also, will tar want to use the current Linux 
partition for anything and run out of room or will it use the Windows 
partition for its work entirely?

Thanks in advance.