If your using a Ron Sutton subframe and control arms, you should probably read this.

[CJD Automotive]

Just an FYI for anyone running a Ron Sutton Race Technology sub frame or control arms. People are already aware of the failures on his two piece, curved design. If you have the one piece lower design, it can (will) fail as well.
Here you can see the crack in the arm. This is on a low 3K pound car, 315's, and maybe has done 30-35 AutoX events, a few track days, and under 10 thousand street miles. If that's not scary enough, the front lower control arm mount is also a failure point. This high load attachment is mounted in a cantilever arrangement with only one and a half sides welded/supported at the bottom, below the load path.
Here are a few pics of one that tore off, and a few pics of the other side, stress cracked, and about to tear off. I'm not posting this to call out Ron Sutton as a hack parts designer and fabricator, although it does make for a happy coincidence, but to let you guys running this stuff know you need to make some changes in the design if you want it to be safe.