Easy to install, immediately noticeable when braking especially harder braking. One thing to note: in the install guide it mentions removing a sticker over the hole closest to master cylinder. On my '16, there was a bracket there instead with a plastic clip that was holding a bundle of wires together. The brace does not support the continued use of said bracket. Not a big deal, just something to note.
GS Master Cylinder Brace
Overall I am very content with this product. There is a noticeable increase in braking force (and counter to this, a noticeable decrease in braking effort applied by the driver) during moderate to heavy braking. I can tell there is less flex in the firewall and the brakes feel less spongy and more tuned.
My only cons:
I would ideally want GS to provide a mounting solution for another wire loom that comes on the 2017 models (no biggie though as creative zip ties solve the solution without being unsightly, and I purchased this knowing it didn't have the mount for it, regardless)
The packaging could be improved. Due to motion in transit and failure to package hardware seperately, the red anodized piece was scratched enough to remove the anodizing, and the bracket itself had been scratched as to remove some of the powder coating as well.
Fix these issues, mainly the latter, and I would give it a full five stars.