Are these compatible at all? Think they would be nice together, just not sure of the mounting hardware will work. Anyone do this? Don't have an Ace, but this would help me decide. Thanks

I would imagine it could be made to work. I have a CNC Warrior brace on my Arsenal Sam 7K, its an awesome brace.  Hard to find in stock.

I have an Ace 5.56 pistol and I also have a SAM7K-44 with a CNC Warrior folding brace.  I was curious about whether it would fit and popped the hinge pin out of both.  The CNC Warrior brace fit fine on the OEM Ace folding knuckle.  It was also a bitch to get the E clip back on the the Ace hinge pin.  The CNC Warrior hinge pin is much easier because it's a tad longer.  I also found that a SAR stock (and I'd assume an ARM stock) also fits those same knuckles though I didn't actually attach it since they're pistols