before anyone says " dont you no what a search button is " etc, i have used the search button but havent really found what im after so im going to ask

..... basically im looking to upgrade my brakes as i have an ongoing project and would like to get a rough idea of what i need to source..... so my question is, is it the 306 which has the 283mm disks and callipers that will fit onto a saxo ??? or have i read somthink wrong lol. also what can i do about rear disks etc or is it best to leave them as they are ?
any help apresiated
btw the cars a mk1 vts