I don't know how to diy can go buy the parts at tradepac then ask them build for me?
for building, u should go to PC themes. Tradepac is more of a buy and diy place.
price wise, def diy is cheaper. bear in mind extra costs from Aftershock goes into things like aftersales, branding etc.
The case is nothing special. Looks like an NZXT S340, which is not their top of the line case. Only thing is this case isn't available here i think. With the savings, u can opt for their top line case, H440 or other cases as u desire.
DIY is a journey. These days, it's easier cos there are so many videos on youtube, websites to show u. but ultimately, its really up to the individual cos some enjoy it, other don't. anyway, i only started recently. and after a few months, realised it's not tat difficult and quite fun actually