I know it's still illegal to relocate the cats and I assumed the rear O2's still wouldn't be happy that far away so that's why I went with the sims. But there's no good reason not to run cats if they really do reduce emissions. That extra 2-3 hp at 6000 rpm's isn't doing you any good while sitting at a traffic light. If the car is driven on the road, it should have cats. If it's a race car then no problem removing the cats. And don't mess with my trees!
