Installing 2.5 with 2.4?

[John Salerno]

Hi all. Just curious, before I do it myself, about the best way to 
install 2.5 if it's the only version I want to use. Should I uninstall 
2.4 first? Does 2.5 replace 2.4? I doubt the latter, but if I install 
2.5, does that mean I need to reinstall all the extensions I had for 2.4 
again, or does 2.5 detect them somehow?

Thanks,
John