I know the std brakes are good i have had a Leon Cupra R

But if you are re-mapping the car by another 60/100bhp it will push the brakes to there limit if you are going the give the car a good thrashing.
Brembo's are a good brake system but they are let down by poor quality soft discs that warp very easy (unless two piece type) if you do not allow a few miles of easy driving to let them cool down.
Cheers
I am going to stick my neck out here and say that I have never been swallowed by the need to upgrade brakes on my current car or my last car which had 312mm discs as standard and vented rear discs.
For sure, I agree that you need better brakes for stopping from speed, and more speed is available when you have more power. However the Cupra brakes are pretty substantial and very good although I echo Z's comments above about them being over assisted.
However, a standard
MK2 Leon Cupra has a 153mph top speed according to the SEAT web site.
There has been reports of tuned Cupras with approx 320bhp making 165mph on a GPS, and one picture I saw at 168mph from a tuned Edition 30. I am unsure if anyone with a full monty Cupra (ie Revo Stage 2 with all the bits) has had it all out, but one would assume that with 350-360bhp, circa 170mph
may be possible.
What I am trying to say is that the only benefit bigger brakes gives is if you drive at over the book speed of 153mph or as mentioned above, track/race the car. I know that 150mph is not something I visit very often in my car, infact only one time since I got it.