if its under 20 mb, dont do it obviously. yesterday i tried downloading it at 500 mb but i clicked preview and it froze and i had to take my laptop battery out. it was agy. if i were you, i would buy it or go to microsoft .com and download the trial for free.
i did that, it took 30 mins and now i have powerpoint, word, publisher an all the rest. the trial lasts two months also.