You are for sure gonna want to order a TKO.Disco is significantly louder than your QB-78.
After the TKO, most popular mods are:1. install a second barrel band, shooters report a good boost in POI consistency.2. Some kind of trigger improvement. You have a few options here: Dennis Baker brass trigger, "three screw mod", gen 1 Marauder trigger group, maybe others. 3. Follow MichaelM. When he gets time he is going to start making internal SSGs for the Disco that will add to the shot count considerably. I have one in my disco that was made and installed by Travis at WAR, I just don't know if he's found the time to start producing them. If he has, that works too. Or make your own of course, but the hammer is hardened. 4. Scuba tank so you don't have to pump. Much cheaper than a carbon tank, and no DOT defined 15-year endlife.
Just go ahead and get acquainted with the gun first before you decide to get the TKO, you might not need it.