Funny, someone on the Kirby boards just discovered this as well (though we haven't been able to get his replay uploaded yet.).
As for the actual matchup... I don't have too much D3 experience, but here's what I've noticed whenever I've played one:
-D3's Dthrow can be followed up by Ftilt or maybe DA if we miss a tech.
-Inhale Break>Footstool>Dair>footstool (again) is too good! Also, our inhale outprioritizes yours.
-Our attacks have less lag overall, but your kill options tend to be safer, and Utilt really, REALLY hurts us.
-We can combo you really well.
-It's not all that hard for Kirby to gimp D3. Also, if we inhale you out of your UpB, I *believe* you lose all your jumps (though I'm pretty sure you can still UpB again) whether we starshot or inhale break.
-You guys might remember DJ_Iskascribble posting a video of my failure of a ZSS getting inhale stagespiked a while back. Well, you might be able to do that to Kirby's UpB as well, not necessarily to stagespike, but to move us away from the ledge and watch us kill ourselves. Yeah, not too big a deal, but thought I might mention it.
-You outrange us by a lot, and you have a better projectile than us (yeah, I know, it might be a bit of a stretch to call FC a projectile...).
-Our tilts mess with you pretty badly.
Yeah, not sure what else to add. As I said, I don't have enough experience with this matchup.