This is an excellent product that has been wonderfully manufactured. It retains all of the factory elements you want, such as the cradle for the steering rack, or the holes for the engine mounts (one round and the other slotted). The fit is spot on and that is no easy accomplishment given the number of points that must be perfect in 3D space. It is obviously lighter and stiffer than stock. This is all wonderful but the best aspect is easily the extra room.
It would be hard to overstate how much more room this subframe creates. The bottom opening on the factory subframe is very narrow and, at the front, tappers to an almost point. This subframe is a wide-open U. At the back, the factory subframe opening is nearly 15 inches while this subframe's opening is over 21. The extra room makes removing and replacing the transmission a dream. The front has so much room you could drive a truck through it. Without a doubt, I could replace the oil pan with the engine in the car now. That alone makes this part well worth it. If I was building my Miata over again, I would have grabbed this part so much earlier in the build.
As with pretty much any part that is welded together and then sent through powder coat - run a thread chaser through any threads prior to installation. This step will clean up any small imperfections in the threads. Other than that, this subframe will slide in without effort. I was stunned at how perfect the fit was and how lightning-fast install was.