Not really. When you upgrade, you wipe out the hacks. Also, there could be code changes in the upgrade that affect your hacks. Programs like Beyond Compare from
www.scootersoftware.com are helpful in seeing what changes have been made and can speed up the process of transferring hacks.
UBB6, which is due out today, possibly in beta form, has some added functionality that might replace some of your hacks and is a complete revision of the code -- so most if not all of your hacks will have to be revised for that.