Is the CZ SA trigger pull or reset improved when the disconnector is removed?
Converting a CZ 75 variant pistol to SAO
alone allows you to use SAO flat Triggers and limit the SA pre-travel with fewer parts and potentially less cost. Additional SA Trigger pull improvements are the product of other tuning options. You can get virtually the same SA Trigger pull in DA/SA configuration with the correct tuning, but it requires more work and may cost more. Most folks are not interested in hand fitting a Disco to achieve what a pre-travel set screw in an SAO Trigger achieves. I think hand fitting discos is fun, but i enjoy tuning as much as i enjoy shooting. The value of reducing the SA pre-travel is subjective and its own discussion.
Generally there is no reason to leave a Disco installed once a CZ 75 variant is converted to SAO
with an SAO Trigger. It could technically cause some unnecessary drag or a timing conflict.
There is one reason that i can think of to leave a Disco installed in an SAO CZ. This is if you want to go SAO while using a DA/SA (curved) Trigger and use the Discos hook to limit the SA pre-travel. DA/SA Triggers do not have an upper set screw for limiting the SA pre-travel and their design dose not allow for the addition of a pre-travel set screw. You use the Disco to limit the pre-travel and cut the wings off. The Disco wings are the DA parts and unnecessary in SAO configuration.
This could also apply if you were using an SAO Trigger without a pre-travel set screw, like the one that comes factory with the CZ 75 SA. You are better off just drilling and tapping to add a pre-travel set screw in this case though.
CGW says that their S2 disco creates an ultra-short reset (which is the best I believe any CZ can be), but I'm not sure how it does this any better than removing the disco altogether.
In a CZ 75 variant, the Disco dose not influence the SA reset distance, only the SA pre-travel. Some discos are called "Short Reset Discos" because they are designed to work with other short reset kit parts. I think that sometimes the pre-travel and the reset distance are both conveyed as part of a "short reset" because its easier to explain to CZ owners that do not have a need for, and will not benefit from, greater than a certain level of detail. This is most CZ owners from what i have seen. If there is no benefit, then there is no reason to drown people in technical detail. If they ask questions, you know they want the details.
As
Minfred mentioned, once you start shooting fast, allot of the fine detail of the Trigger dynamics tend to grey out. I am still going to tune the crap out of them because it is fun. Reaching the absolute maximum potential of a mechanical system is its own hobby.