400-500whp is a big ask that would require some serious serious serious work. In saying that front brakes, theres levin twin pots or celica that require some mods to fit or spend the coin and you can get some willwood front brakes, around 1200AUD I paid. There are K sport 4-6 pot and so forth but be prepared to fork out some good money for them. Rear is not too bad with some good pads. Stock front brakes are actually quite good if its in good condition.
Other than that, all the best with your build