The differences between them are pretty much that the ultimate versions have backlighting, and the stealth versions (I think) have the characters written on the side of the keys instead of the top. Though I'm not sure why you'd want that AND backlighting.
That being said, if you're looking for a mechanical keyboard, the blackwidows are pretty much the WORST of the bunch. They're very poor quality, use propitiatory keys so you have to buy their replacements, and simply feel like POS.
If you want a good budget keyboard, look at the Cherry 1800 or better yet, the Rosewill RK-9000i.
EDIT: Also, I can't quite tell, but is your profile a Lotus Exige? If so, very nice. My dream car is an Elise S. *sigh* Someday...