1) If it has SP01 in the name, it means long dust cover with pic rail at the bottom. If it does not have SP01 in the name its a short traditional dust cover.
http://www.czub.cz/en/cz-75-sp-01.html
http://www.czub.cz/en/produkty/pistole/cz-75-shadow-line.html
2) if it has "shadow" in the name, it means it has:
- fiber optics front sight
- no firing pin block
- 2 side enlarged safety lever
- rubber grips
3) if it has "shadowline" in the name, it means its "shadow" plus the following:
- competition hammer (~$100 part, can be installed on your own)
- aluminum grips (~$100 part, super easy to install)
- steel recoil spring guide rod (instead of plastic one, super easy to install)
- slim 2-side safety ( smaller than shadow, ~$50 part, can be installed)
4) there is also a "shadow mate" which is shadowline plus gunsmith polished parts and extra springs and I think adjustable rear sights. But I don't think they make it anymore. If you want that upgraded edition look for "Canadian Shadow" or "Shadow Orange"