Lumbuscobob

So, Im really torn between the stillen cbe and Fast Intentions cbe (not to mentions non-res, 12 and 18). So heres my situation and id like to see what you guys say. My car atm is completely bone stock, i am going to be putting a g3 intake at the same time as my cbe at least and a tune AND if someone could push me towards it, maybe headers or hfcs but probably not. So my Z is my daily driver and i hear that F.I is the way to go (because the product is amazing and costumer service is out of this world), but is there any drone, how loud is it and should i get a 12" res or 18"? I am driving on the highway and city quite a bit because i will be living in LA. Stillen on the other hand is just a pretty solid exhaust but idk if it sounds nice. I want a loud (but quiet enough for daily driving), deep but not raspy or "droney" exhaust tone. Thanks For your guys opinion and help!