Save yourself the headache & get the tuner now - you'll be glad you did & it pays for itself in the long run when you don't need HD to flash ECM with every UG. This way the pipes can stay as is (no welding) and the $$$ you're dumping into adding bungs to pipes can be used for tuner.

 

Same problem for me. No O2 holes. What fuel management do you recommend I get?

 

There are a few fuel management systems (tuner) that come with O2 eliminators. You simply plug the eliminator into the wire harness leading to the ECM. Easy and quick.
Two companies that I'm aware of carry them. Dobeck/Techlusion & Fuel Moto Micro .
I recommend calling both companies, and would think Fuel Moto carries more then one model that eliminates the O2 sensor.