1. Can an underfolder stock be installed on a Sar-1?

yes, but it requires significant receiver modifications.

What modifications must be made?

rear trunnion swap and milling of receiver siwall openings/rear receiver contour.

2. Where can I buy an AK-74 brake? (non-krink)

k-var www.k-var.com

3. Can a Krink side folder be installed on a Sar-2?

yes, but again, very significant machining operations need to be performed.

What modifications must be made?

rear receiver contour, hinge relief, latch openings cut, rear trunnion swap, front latch window cut, front latch pivot pin holes drilled.

4. Where can I buy a dust cover for an AK-7

k-var.