those numbers aren't good at all man. Dont let chris talk, he doesnt know what hes saying. 241 is around what a bone stock TTZ should make to the wheels. At 12lbs you have some serious issues. My stage V++ TT at stock boost (10lbs) made 290+...at stock boost...as for the wideband, you dont necessarily need a bung welded on for them to take wideband readings. They can use a coupler with a metal pipe that has an O2 sensor in it and attatch it to your exhaust. Thats how mine was taken. Your curve definately looks like shit, it peaks then just drops. I would definately check for vacuum leaks, you'd be surprised where they can spring up on our cars.
Just for reference, heres my dyno at stock boost..
