Yes, I would. Quite possibly, Mac OS X 10.4.x is the most important component in resolving your problem, because it includes the Sync Services framework.
Once you have updated to at least Mac OS X 10.4.8, you can download the Missing Sync for Blackberry, then read the User Guide, install it, and run it as a trial package. That way, you will be able to determine if it meets your requirements. Use this link to do so:
http://www.markspace.com/downloads.html
Look down the page for the section labeled
The Missing Sync for BlackBerry and use the link beneath
Available updates.