Budget Y pipe: JIC Magic or OBX

PR370z

Instaled my JIC magic y pipe today, the quality of this pipe looks really good. The sound is definitely louder/ deeper mched almost perfect to my ERZ HFC's (around a 2.3'" inside diameter). But on the back end the y pipe has around a 2.8" ID and the stock exhaust is around 2.3". Should I leave it like that? Should itry to make the stock exhaust a little bigger (grinding or sanding)? I there any noticeable hp loss from this?

Thanks for the help

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MODS:293 Whp/ 246 Tq K&N drop ins, ERZ HFC, JIC-Magic Y Pipe, HPS post MAF tubes, Nismo shift knob, 30% tints, JDM rear fog light more to come!