Might as well just go for 312mm. Does the job more than well enough.
I havn't driven a Cupra, but I'd wager that the brakes aren't worth 2.5 times the cost of a 312mm conversion.
if you want braking performance over looks then i'm sure you can get uprated grooved discs (which is what i'm aiming to get once my standard ones are mullered). these will look good too
Just a point to note.
If ya go for bigger disks it can affect the performance and handling of the car be your increasing the moment of inertia of the wheel.
If you've seen that top gear episode where they take some ugly looking renault and try and make it as fast as an evo. The first thing they did was to get some wilwood calipers and disks which meant they had to buy some bigger alloys so they would fit over them. Stig took it round track and it was 2 seconds slow than the first run.
Your also increasing the unsprung weight which can reduce grip.
At first glance that site does look good, but if you go to actually order them they charge you a surcharge on each caliper. You end up having to pay 188 quid for em! The only way to avoid the surcharge is to give them your old calipers but I think you have to swap "like for like"?Just found this web site http://www.car-brakes.co.uk/ found tt caliplers new for 60 od quid each, is that good? anyone herd of this company befor?