Removing the Trigger Housing without removing the Bolt Stop Lever.
To avoid confusion I had better define the terms I use in the following paragraphs. The "bolt stop" is the long black lever, shaped like a letter L, that fits inside the trigger housing. It pivots in two slots at the front of the trigger housing and it is held in place by an extension of the trigger spring that fits into a grooved arm on the pivot bar of the bolt stop. The "bolt release lever" is the plastic lever, on the left hand side of the CX4, that is pressed to allow a cocked bolt to move forward and carry a cartridge into the rifle's chamber. The "bolt release lever" is, of course, connected to the "bolt stop". The connection is made via a projection on the bolt release lever that goes through the side of the lower half of the rifle and through the wall of the trigger housing. This connection must be released before the trigger housing can be removed from the lower half of the rifle.
As mentioned previously, replacing the bolt stop is a pain. During reassembly of the trigger group inserting the bolt stop into its two slots is simple. The difficulty occurs in positioning the trigger spring extension back into a groove on the bolt stop after the bolt stop is in position. A spring hook, as mentioned under "Special Tools" certainly makes this process easier. Even easier is to avoid removing the bolt stop in the first place. The bolt stop must be removed to work on the trigger but it can be left in position if you are only working on the hammer.
Under normal circumstances the bolt stop must be removed to allow removal of the bolt release lever from the trigger group . The bolt release lever can actually be removed without removing the bolt stop. Using a screwdriver or suitable lever push the bolt stop towards the rear of the trigger housing as shown on the Tactical Excellence website. HOWEVER, prevent the bolt stop pivots from jumping completely out of their location in the trigger housing. By manipulating the bolt release lever - honestly, this can be done with only two hands - you will find that you can disengage it from the bolt stop and remove it leaving the bolt stop to return to its normal operating location in the trigger housing. The cross-bolt safety can now be removed as per the Tactical Excellence instructions except that it will be necessary to gently lift up the long arm of the bolt stop so that it does not interfere with the removal of the cross-bolt safety.
While the bolt release lever and the bolt stop are separated take a look at how the connection between them is made. Having this knowledge will help with reassembly. The bolt release lever has a mushroom shaped projection that fits into a slot on the bolt stop arm. There is a hole in the bolt stop arm large enough to permit the mushroom shaped head to pass through the bolt stop arm then the "stalk" of the mushroom slides into an elongated slot in the bolt stop arm securing the two parts together.
During reassembly of the trigger group the release lever can be reconnected to the bolt stop by using the same procedure as the removal process. Simply push the bolt stop rearward to allow the mushroom shaped head on the bolt release lever to pass through the hole in the bolt stop arm then allow the parts to slide into their operating locations.