[CentOS] upgrade from Fedora Core 5

Hi -

It was recommended to me on the Fedora list that I consider upgrading to 
CentOS 5 from my present FC5 - the machine is used only as a light-duty 
CLI-only server. I have a couple of quick questions in that regard:

1. Is now a bad time to install CentOS 5, what with the root exploit out 
and about?  Should I wait for a new kernel?

2. I just picked up a Cavalry 1TB external USB HD, the CADB001U32, which 
I want to use for backup purposes.  I formatted it with one ext3 
partition.  If I load all my data onto that drive, then upgrade my main 
machine to CentOS 5 (which I assume will involve a complete wipe), 
should I then be able to mount it and retrieve the data?

Thank you very much.