I am upgrading my boiler this summer, should i also upgrade the radiators?

i am probably going to rip out my 1970's glowworm 30b mk2 and install a Worcester Bosch 30Cdi this summer, should i also install new radiators and should i change the pipe work from the existing micro bore 8mm to15mm?? is this the best boiler for a 3 bed 1930's terrace, 2 adults and 2 kids, 8 rads....any advice appriciated!!