big brakes - primary jobs is to disipate heat quickly. Upgrading to bigger disks and multi pot calipers will not decrease your braking distance on their own. What they will do is change the braking balance and feel through the pedals.
So to stop faster you need to do two things, reduce weight transfer to the front by fitting the best suspension that you can and also by fitting the best gripping tyres you can afford.
If your car can lock its brakes it shows that you can apply maximum force before the traction between the tyre and road is broken. A big brake kit will allow you to do this more times before brake fade will be an issue.
To increase that friction co-efficient between the road and tyre you need sticky tyres. If you are happy running cut-slicks during the summer then do it
Our 205 rallye trackcar ran £3k suspension on it, cut slicks with standard pads and disks and it could outbrake a friends Ibiza Cupra R with 4 pot Brembos.
I know many people find it hard to see the logic behind all this. if you disagree ask yourself this.
Why do my brakes lock quicker when the road is wet?
Its the same principle but in reverse