I have to agree with you all as you're all right imo (Jetpilot, Dan & Nic).
My FI Zed was running Goodridge s/s braided brake lines, Motul RBF600 brake fluid, Ferodo DS2500 pads & EBC Turbo groove discs ~ definitely an upgrade from the standard set up but not by much.
I found no problems stopping my Zed even when abused on track for several laps but without a doubt a BBK (Big Brake Kit) would have been beneficial. I did find myself pressing harder on the brake pedal though when spiritedly driving on the roads I know as Dan mentions I found myself approaching corners at a higher speed than before the car was FI.
In short it is not essential imo to have a BBK before going FI but it is definitely beneficial/sensible to upgrade the brakes as much as possible and ultimately increase your stopping abilities ~ that goes for any FI or N/A car though.
If I had kept my FI Zed then a BBK would have been a future purchase for sure as I love driving my cars fast, hard & safely.