Uncle Sam says I have to use the Cats. I am setting up an off road mod for when I autocross and drag race, as well as my daily driver. The main difference will be the CATS, fuel pressure regulator setting, and the air pump if any. I will have the exhaust shop build a pair of sweet large diameter pipes from the collectors into a custom H pipe back to the mufflers. This way I can bolt and unbolt the entire system Cat free for racing purposes. The stock system works the same way basically and with collectors welding into the front I can bolt/unbolt. Long ago we ditched the precats in favor of one center cat. Have never had a problem passing emissions tests as long as she is good and warmed up.
I could not believe how easy the Headman headers went on the car last night. I was prepared to fight, ding, bend, heat cut the bolts down, etc. etc, but they popped right in. In fact what makes this an even greater pleasure is the fact that I called Summit and asked for the cheapest headers they had to fit the car. The muffler shop will cut and weld the O2 bung for my O2 anyway, and I am looking into what to do with the air pump as you know here.
In looking at the LT1 air pump systems, they don't have an individual injection tube in each cylinder. They have a single injection tube in each manifold, and of course the CAT. My S10 had only one tube in each manifold where all the cylinders collected. So I don't see a big problem welding in a port in the collector while also doing the O2.
Anyway still researching that. I had a spare air pump that I disassembled last night and removed the inner pump fins. When I reinstall it will basically only be an idler pulley, and I am saving the original one and tubes in the event the electric does not work as intended.
My thinking here as well is you typically can get away with a newer engine in a car as long as it at least will pass the emission standards of the year model the car is titled as. So, if I am using a newer style emission design (electric) I can't imagine a visual test being a problem.
BTW, we no longer have emission tests in my area. However, I have learned the hard way over the years to plan ahead. No better time like the present since I have it all torn down.