downpipe or manifold

So I just got a Fullrace 3" catless downpipe installed on my 2013 civic si coupe. Now I know since its catless that it will throw a CEL and to my knowledge if you use a flashpro to disable the "P0420 catalytic efficiency error" then the CEL should go away , right? Well I did that and when I...

yea yea i know its not out yet, but i felt like asking and getting this off my head lol......what brands have good exhaust systems that i may want to look into once the 9th gen civic comes out and their product comes out for it? a friend told me magnaflow was good, and i dont want any ricer...