<< So Nothinman, Will there be any decress in speed ? >>
Not a noticable one. Read the FAQs, I think there is information about this there, or search anandtech forums. They arent all that big, but they have plenty of info (especially the OS forum, plenty of info about NTFS).
<< also , how should I go about changing .... As above (And Should I reformat then delete my partitions , and partition again? IE( I currently have 2 partitions (30 &30)) >>
You can either convert it as in the FAQs or reinstall and setup NTFS then.