If you are going to be circuit racing you will need vented disks, but you dont need 32mm or 36mm gtr disks, they will cool far to efficiently for such a light car. Disk diameter has the most affect on light weight cars.

We have just finished developing a new 280mm x 22mm 4spot brake kit with custom ally hub with coil-overs and camber tops with a total weight of only 20.5kg per side.

This set up will fit under 15inch wheels and some 14inch. And is avalible in 4 and 5 stud.