mc,
First time I've heard anyone call the CZ a Hi Power clone! Just pulled a Hi Power out and did a quick comparison to the Witness. Can't seem to find many similarities, other than the fact that they are both magazine fed semi auto pistols. They appear to be quite different in just about every way otherwise. No matter, I'm quite fond of both!
Savage
edit: Forgot about the Browning Linkless cam locking system they share.
When the 1st CZ 75 were made they were single action and even used the Hi Power magizine. All controls were in the same place, browning long delayed blow back. Brno (CZ) Reversed the rails and made the slide smaller as they had a problem coping the Browning slide Or getting that large of a bar stock after the war or it was the standard bar stock for the TT-33 or something Makarov. I forget the whole story.
Once they changed the gun to Double action all bets are off and through the years parts were refined to make use of the latest stamping and technoligy.
Also your Trafalgio ( Witness) is an Itanlian copy of a copy with further refinements. The Witness had the ability to go from pocket pistol calibers to (32, 380, 9mm, 41 action express, Later 40 S&W, 45ACP and 10mm if I remember right, Maybe not 32 that may have been the Wolf auto) by changing uppers slide assemblies and mags. Maybe it was only the barrel, spring, It has been a long time since I had a Witness in my hand. I was going to buy one back in 93 but got moved out of the state before I could complete the transaction. The 10mm will not fit in a standard CZ-75 from CZ and CZ later came out with a copy of the Witness in the CZ-97 in 45 ACP that they too tweeked. As I said earlier not all CZ-75 mags work in all CZ-75 as it is one of the most coppied hand guns out there and as everyone copies it they tweek (california word- Never heard it till I moved here) it a little to take advantages of new materials (stainless, polimer, alloys), processes (mill, CNC, Investment cast, molded) as each company gets involved in making them.