im planning to buy a Homunkulus Sword for 8m.. and i saw a Homunkulus Sword w/ Acumen for 12-13m.. is it worth it?? or should I rather take the quest??

On what server u play?

to put a SA you have to pay around 1 mil for the fee on a C grade weapon
if you want to buy a SA cry level 7 (red 7 for acumen) you can buy it for less than 1 mil in cry at luxury so it cost around 2mil to put it on your homu
if you level the cry by yourself which is really fast (cry don't break anymore) you can just get a homu acu for around 9 mil
btw, buy a darkscreamer with C and D cry (it will cost around 6.5 up to 7 mil depends how much cry cost) and convert darkscreamer at BS of mammon into a homunkulus for free, you will be able to get a homu acumen for around 8 mil
if you plan to overenchant your homu, try it on darkscreamer, darkscreamer have better chance to be oe'd than homu (on offie, its a little trick)