Patch Upgrade for SAP NW 7.3 from SP05 to SP10

Hi SDNers,

We are planning to perfrom a support pack upgrade of our SAP NW 7.3 system from SP05 to SP10. As part of the analysis prior to the upgrade I would like to know a few things :

1. What are the main watchouts when upgrading from one SP level to another in terms of applications such as web dynpro for java, CAF apps, BPM, etc ?
2. If my web dynpro apps are on a lower sp level and am planning for a upgrade to a higher sp level, what do I need to consider in terms of tracks, DCs, SCs and NWDI ?
3. Are there any resources or links or notes that I should consider before the upgrade ?

Any help for the above would be highly appreciated.

Regards,

Sundar.