I wouldn't recommend just syncing you 270 data to your 650 (except your addresses and datebook entries via Outlook).
Get the
NeatFreak pack and install them onto your Treo first,
Perform a hotsync to get your contacts and calendar entries onto your 650,
Then, add apps one by one and launch each one to make sure that it works on the 650.
If you have to remove a program, use the Clean Up apps to make sure that you delete all related files.