Been a long time since I owned a Disco, but gotta say (with only the best intentions)
IF you have a drill, why spend anything to start off with?
Use some elbow grease on the trigger, Crosmans triggers are generally horrible, but can at least be smoothed out/made predictable with good polishing. Sometimes adding bearingtip screw can change a trigger completely.
Recrown, I would ALWAYS attempt it myself at least 1 or 2 times first.
Extended bolt probe, easily done. Cut off existing bolt just past the o-ring. Drill a small hole. Insert a finishing framing nail cut to the desired length and epoxy in.
I personally (on most any gun) will spend a max of 20 bucks on the gun and have it shooting better.
IF I were to spend any money to start, it would be on a proven trigger insert of some kind.
Then spend the rest on pellets