I recently sent off to the good old USA for some allen/hex headed action screws for my .22LR CZ Varmint. Paid by paypal they took 5 days to arrive, I also bought a silicon bolt spring from the same company J&P custom products LLC. I fitted the screws, they match the standard trigger guard well and appear high quality, they made using my in lb torque wrench easy with no fear of slipping as with a normal screw, CZ's seem sensitive to screw tension. The bolt spring is apparently 10% stiffer than OEM, though I have not fired the gun yet, dry firing somehow seems crisper. all in all good products.

There are a plethora of comments re the above on RFC.