[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.