Genos has some good prices and I have purchased from them also, but if you have a Cummins authorized dealership close by, you may check with them on the Fleetguard filters. I have a place less than a mile from my work and have found the Fleetguard filters there a little cheaper than Genos without having to wait for shipping and add cost to ship. Otherwise I would probably still be purchasing from Genos.
As far as oil I use the Delo 400 15w/40, but would not be afraid of the other brands Rotella T, Delvac, etc. A guy at my work uses the Rotella T on his 02 CTD, he ask me about what oil brand I use, and I said Delo, he said I was going to use Delo, but this guy told me it's bad about foaming so I went with the Rotella T. :-laf
Tony