If I were doing it, I would pick up the Outback-IID and just use it as is. The important thing with this suppressor is to disassemble and clean frequently, and if you do, it will last a long time. Be sure you get the manual with it, and if not, call us for a copy or download one from our web site. Maintenance is a little more of a pain in the ass than with our monocore, but first round pop on a pistol is insignificant with the Outback.
To the best of my knowledge, we are not doing free IOU upgrades. Our GM22 or the IOU basically use the same monocore, and cleaning is definitely simpler. The increased first round pop on the monocore can be mitigated with a small dab of grease or Vaseline on the back. After the first round or on a rifle, they sound the same.
I recently assembled a .22 can for a personal project, and I did it as an Outback-IID.