I actually posted this on another thread, but it will apply well here too:
Here is some interesting reading for ya. Scroll down to where they are testing the 350Z performance brakes (non Brembo)vs. the track brakes (Brembo). Less than 2 feet of difference in stops below 80 mph and less than 5 feet of difference for all speeds above.
http://www.zeckhausen.com/testing_brakes.htm#
Oh look a chart... I like charts...
http://www.zeckhausen.com/testing_brakes.htm#Summary
The brembos don't significantly improve the braking coeffecient, the just dissapate heat better.
Coupe Pearl 5AT Leather
Z tube and K&N drop in.
Fujitsubo Y pipe...