The main differences between a stock (from the CZ UB factory) SP-01 and a Shadow is, on the Shadow:
- No firing pin block (as found in the 75B), for a crisper trigger pull.
- Extended mag release
- Larger/Extended safety
- Fibre optic front sight
- Competition rear sight
- I believe it also comes with slightly lighter recoil and main springs to lighten the trigger pull
The Shadow does not come standard with a Combat Hammer to make the trigger pull crisper, however this is a popular modification done by IPSC/USPSA shooters - the Shadow usually ships with the same Hammer as found in the standard SP-01.
On that note, there is a difference between the Combat Hammer (which is an official CZ UB part and meets the IPSC Production rules) and the Competition Hammer (which is a CZ Custom hammer, which does not meet the IPSC Production rules as it is not a factory part).