Well guys, I think it all has to do with power and weight...
For my car 1270kg and 155bhp, the brakes are truly great. I had 2 serious track days till now and there are no minuses.
BUT, putting these on a 300bhp mk6 GTI (if you have lets say stage 2 or, 260-270 bhp for stage one) is, I think, not enough for serious tracking. It will work truly well for everything but extreme tracking. The way I see it, the discs are the weakest link in this setup. I think they are too thin.
About the Polo GTI, I think this bbk is ideal for this car. It weighs about the same as mine but with more power (especially if there is a stage 1). And, it also allows for 16 inch rims (this was one of the selling bits for me).
As I know the stock polo GTI brakes have 288mm discs. Am I correct? I think the back has 256mm disks. If this is the case, I had these brake as standard. Now I have this BBK with stock GTI rears (286mm) and this works fine.
One more thing that I really like about this bbk is that it comes just like you want...
When looking around for BBK I noticed some BBK have drilled discs (not quite you want if you track a lot) or DS2500 or similar pads as standard. After talking with DaveB I realized what pads and dics I needed and now I have the setup that suites me.
I like this kit a lot!
With a lightweight 2 piece disc (I am not sure if DaveB can provide these, but, for example Tarox can for 600 EURO a pair
) this setup is also a very very light one. Caliper 2.5kg + pads 0.5 kg + bracket 1 kg + lightweight disc ~ 5-6 kg (stock is 8.6). Please correct me if I am wrong but these figures are from memory.