You will love it. You could do as much or little at you want. Out of the box they are great and I think it's my favorite gun to shoot.
I got the comp hammer, an aluminum trigger, Dawson fiber front and Adjustable rear sights, large CZC magwell, aluminum grips, CZC 140mm basepads plus CZC mag springs and followers.
I have also done a lot of work on grip modification, frame shortening, and etc.
I use my TS 9mm for 3 gun and I bought a Czechmate slide racker but haven't installed it yet because it wouldn't be legal at a match that I will be attending next month. My only complaint with the CZs is that it doesn't leave you with much real-estate for racking the slide. Short of the slide racker I have put quite a bit of state tape on the rear of the slide to make it a bit easier for those empty chamber starts. I have also considered slide lightening in some strategic patterns to make it easier to rack the slide but no specific plans yet.