from 16mhz to 8mhz

Will I lose any functionality if I put the chip on a board without a 16mhz crystal and program its fuses to run at 8mhz? Would I need to change my code? Will the serial functionality still work? What would happen if I put a chip set at 8mhz on a board with a 16mhz crystsal? Thanks,nik

please read this thread:

you can even use the internal 1mhz oscillator: