and yes the stock o2 gasket is not divided...

 

Personally, I would port it out in the aera the wastegate gases merge into the 2.5" down pipe section, make sure it flows nicely into that section. I always keep the gases divided to keep the turbulence down, this in theory will improve flow.
Hope this help!
Collin

 

ill be sure to hit it with the trusty dremel when i get off work...lol

thanks Collin!