Paid 286 for the 5 inch, which is not compensated. The extension just LOOKS like a comp. Barrel and sleeve are not cut. Adds perceptible weight, though, to counter barrel rise.
Disassembly is cake. Extension has a setscrew on top, just aft of the front sight, plus the two on the side below the barrel.
As noted, Earl's has the 3.4 inch barrel kit for 60 bucks plus S&H. If you get one with the 3.4 inch, the 5 inch kit is 75 plus S&H.
Works for me.