I agree with Dan. I took my forge muffler delete off because they do absolutely nothing, other than deleting the bayonet. I also tried a discharge pipe kit from some brand I can’t remember and again, precisely squat.
People fall into the trap of believing the ‘bigger is better’ marketing hype. The oem pipes are designed to keep the gas speed up. It’s not for deliberate restriction reasons the discharge pipe starts off at a seemingly pathetic ~45mm ID and very gradually increases to ~63mm ID just before the bayonet flare. Little turbo, little pipes. Big turbo, big pipes
Maybe replace the plastic pancake pipe with the K04 metal pipe? Does it fit a K03 turbo?