Don't waste your money on a big brake kit. You can only stop as fast as your tires will let you; if you can lock up your tires (or trigger ABS if you have it) you will NOT see *any* improvement in stopping distance from bigger brakes. If you want a brake upgrade, flush your fluid, put in SS lines, and stop buying parts-house brake pads (they ALL suck, especially the lifetime warranty ones).
Bigger brakes exist for ONE reason: heat management. If you're driving hard enough to see brake fade (which is nigh impossible on the street), only then will you see benefit from bigger brakes.
Other than that, bigger brakes are actually detrimental. It's just a big mass of unsprung weight.