Downpipe advice
 

Hi evryone,
Getting my V3 mapped soon,& was wondering if my downpipe will be good enough. Don't know what make it is, it's 3inch to 2.5 flange decat, but instead of full open mouth it has a separate pipe on the side where the restrictor would have been. I'm hoping to make 400 bhp & don't want to fail because of this. Should I go full open mouth RCM etc. Any advice appreciated. Thanks.

A mate looked at it & thinks it's a good one, but someone else told me a full open mouth is the only way to go. Help I'm confused thanks.

Anyone?