If I remember correctly from their website, there is a link to a cross-reference chart to give you the correct filter number (I'd post a link, but it's probably a violation of the TDR guidelines). That said, it appears to be part #57620. I would call to make sure.
As for whether it's good enough or not, I cannot comment on that. I have used the FleetGuard Stratopore for mine since new. They're about $11 each, which is twice as much as the Wix. Since that filter is sold by Cummins, it's what I will keep using. I use Wix on my Honda, they appear to be great filters. As for me though, I'll stick with the FleetGuard's on my CTD.
Truth be told, they're probably the same thing. Do a search on "The truth about filters". There was a pretty good thread recently about who makes what...
Hope that helps,
Andy