I have one on my car Tino since day dot. The theory is definately there, if you stand with your head in the engine bay and get someone to kick the brake pedal you can see the flex involved. I have the Cusco one installed and have tightened it up like a mofo, and the bracket itself still flexes. I'm unsure of what % difference it makes as I've always had it plus the braided lines and brakes etc, I'm sure it reduces the overal flex but certainly doesn't eliminate it. I would be looking at getting one custom made to fit your engine bay and getting it made more solid than the Cusco one. Its now on my list of things to re-do.

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MY93 Impreza GX 1.8L, 0hp, 0nm