that depends on you whether u wanna add a box or not...U can also have yourself a CAT in between the piping too...if u want to, I would take that as a silly act, replace it with a bullet ;)
straight out pipes, known as tangki bawah goes under the petrol tank, so do u think it's noisier? With more fuel consumption obviously
Straight out pipings will give better pickup(according to JIAN HANG's Ah Wah la), while original route will give u a better end :lol:
happy moding though bro, everything is up to you, the best is u go and get some advices from the experts exhaust shop