Does anyone see any issue in eliminating the air line that runs down to the cat? This is only used to help light it off initially, correct?

SB

You can eliminate it if you take the rest of the A.I.R. system out too. You can't realy remove it from the cat unless you have a welder to close the hole up with (talk about an exhaust leak!!).....what you can do is cut it off a couple inches from the cat, fill the end with JB Weld, and crimp it down with some really big pliers. Once the JB sets up it'll be sealed real good.

You can just saw the line off about 1/2" away from the converter and use a hammer to seal it off, if you do it right it will close tight enough that it won't leak.

Wrong. AFAIK, when you look at the air diverter valve, you see it has tubes going to the AIR inlets on the manifold. This would screw up O2 readings. What the ECM does is open it up when the car is starting for emmissions and it does screw up the O2 readings but we don't care because the car is not in closed loop where the O2 readings matter. Later, it will shut it off and go solely to the cat. During open loop, it will go to both cat and manifold.