On a 98 converted to DSTs the only change is a "lever" is installed where the original trigger would be, the sear and the rest of the bolt ect. are not changed / modified. you will need to modify your bottom metal & stock to accept the DST module . Some Brnos are an exception - the triggers in mounted directly to the bottom metal.

Yes they can be pricey, you could look for a used set, the basic units are all much the same. You'll run into a fair # with the back triggers removed - too complicated for some I guess. I just wish they'd keep the trigger under the butt-plate / somewhere. FWIW --- John303.