Our user
Artemmka from Lettland (speaks englisch too, so ask him) has Mazda 6 GG (non-MPS) breaks in his Xedos 6. I had the pleasure to drive his car on one of the last Xedos meetings and can confirm that it breaks far better than the original Xedos breaks.
As I remember you also could use Mazda 6 MPS breaks too, which should be really far better. Assumed your rims are big enough for that large brakes...
Regards,
Christian