the "performance" 02 sensor is actually a fake O2 sensor, it plugs into the harness where the O2 sensor goes, but dosnt actually go inside the exhaust stream, it sends a constant 14.7:1 ratio to the engine i beleive, perhaps a bit richer, say 13:1 or so. so you would have to plug those in and seal off the holes where they originally went. as far as moving them down the exhaust, wont work, still screw up your plugs, i would recomend the high flow cats, random technology makes them, and they work great, have one on my RS, whats left of her anyway lol.
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Chevrolet Camaro - I enjoy beating the hell out of people
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