Not too long ago somebody ran a series of tests on the various fuel maps that the tune resistors gets you. The fuel map for use with the cats does run very rich during acceleration , though they all run about the same when at a steady speed and the engine is warmed up. But simply removing the cats wouldn't cause the engine to run any different, as all measurements are taken before the cats anyways.
Though the exhaust will be extremely polluting in comparison to running with cats, I found this out due to the previous owner gutting the cats on my truck and passing inspection was just impossible without new ones.
My oil line fix
My 100k stopped odometer fix
Brace for impact, I'm in a "modifying mood". Massive thread count inbound.