I had it in another thread a while back, but I don't need the firewall plug. My car was s misbuild; Symposer parts were missing from the valve on the battery box to the firewall. My guess is they didn't drill the hole in the firewall and just left the associated parts off after that. Quality :-/ I initially thought I wanted it fixed, but now with a Cobb cat back, I think I have enough noise in the cabin anyways. So for me, I never knew what I was/am missing. Getting a plate just to clean it all up.
Question though...what about the valve assembly on the battery box? It won't throw a code or CEL from unplugging that will it? When you guys delete this, are you gutting the whole system or are you leaving that valve so you can leave it hooked up?