When upgrading Citroen AX suspension set up; alot of owners also upgraded the brakes for a bigger and better brake set up usually from a 4 stud setup. The most popular set up is the Bendix calipers found mainly on citroen Saxo VTR/VTS and 106 GTi. These calipers are fitted to a wide range of PSA vehicles, 306's, 106's, Xsaras, and some C2's. The new calipers give a larger contact area with the disc, and the discs tend to be bigger and vented, therefore resulting in better braking. To further improve the braking power, different brake pads and discs can be used; for example: drilled, grooved or combi discs, or higher grade brake pads.
For those who already have 4 stud(AX GTI) the Saxo VT* and 106 GTi calipers will bolt straight on with no other alternations, the same calipers can also be found on middle spec 306's and other PSA cars.