Your not really making your own if you're buying an intake with a filter...
Just buy a 3" 90 degree pipe bend, and look on k&n's website for a filter with a 3" outlet, they only have 3 or so choices. Pick one LxW that fits best. You can get the ones with a filter cone part on the top of the fiter as well though. Forget what its called, but it adds more filter area.
Everything can be bought from summit racing once you get the part number you want from k&n's website.
I am but I can't find the part numbers, just need a number for a refernce. I'm going to 3" 90 degree pipe, I was looking at the typhoons and how they come with an xtreem filter so I was going to put an xtreem on mine and wanted to know whats the part number on that filter.
Thats the number on the actual pod, i doubt there is an actual kit number for the 280zx, if i were you i would just get a 3" pipe bent up, or even mod your old intake pipe to house it, it shouldnt be to hard.