2014 kawasaki z1000 Exhaust system

Hello,

I am thinking of buying KIMISS Motorcycle 4-2 Front pipe Exhaust header for my Z1000 but i don't know if the quality is good. Does anyone have any experience with it? Any advice? What are the cons?

Also if this is a bad or not worthy purchase, what header would you recommend? I am going for a sound that is louder than just a slip on but also not super dooper loud and under $400 if possible?