Query on Tamiya Group C Chasis upgrade

HI,

I would like to modernise my old group c chasis for leisure drive.

Any C Hing know if F104 or F103 rear assembly including: rear shaft, gears and rims fit with the old group c chasis? or simply get the whole F104 / F103 rear assembly would be easier?

Also which shop at KWS has most of the upgrading parts for the chasis?

Thanks very much.

Thanks !