xsara vts rear-brakes upgrade?

I have just bought a fine 2002 xsara vts and I' d like to disable the ABS brakes and upgrade the rear brakes to put more bias onto the back.
Does anyone know,
What other bigger brakes would easily fit onto this Xsara ?
If there is anyway to disable / replumb the abs (other than unhitch the wire which works but leads to 3 dashboard lights and computer warnings and MOT failure) ?
What about the handbrake?

Any advice would be helpful, anyone who rally s these cars must sort the brakes a lot.