Yes, you need the INT2 hack. :-)
It says so in the manual too. ;-)
p.s. the card may not work so well if:
- you are using some devices on the native A3K SCSI chain.
- you have DMAC 4 and Ramsey 7 chips (yes, the newer revisions)
Phase 5 never really tested CSPPC in A3000 units with newer DMAC/Ramsey revisions, but only with the old ones.
Also make sure that you set the jumpers correctly on the A3K motherboard (info available in the manual).
It may be possible to still use the native A3K SCSI, however usually there are conflics between it and the CSPPC card.
Go to
http://amiga.serveftp.net for some very clear instructions on how to easily do the INT2 mod.