4wd info needed

hi all
       iv just bought a g60 syncro gearbox and audi ur quattro rear subframe and diff ect

what i need to know is will the ratios in the diff and the final drive of the gear box match up or will i have to buy a syncro rear diff?

need to know this as i will be running serious power through this set up and i dont wont the rear wheels trying to over take the front with gearing not bein correct

any help will be usfull help

thanks
gaz