I got EBC Turbogrooved discs all round and Ferodo DS2500s pads all round for something like £600 so you don't have to pay prices as high as the ones you have been given for OEM parts. Get some braided lines and Motul RBF600 fluid while you are at it for good measure.
It depends what you use your z for though. The above combination is as good if not better than the OEM set up and half the price, but wouldn't stand up to track days as well as many other (typically more expensive) brands.