Hi Rob, The overall exhaust smell will become stronger and prevalent with no cats. When driving the car you won't notice it unless you have windows down and at a complete stop with windy conditions outside. You may get a little smell in that situation. If you start the car in the garage and let it sit for too long you will of course contaminate the air with exhaust fumes but that would also happen with cats. In the winter you really shouldn't start the car unless your driving it. Letting it sit while running is not good. For winter storage fill it up with a full tank of gas and hook it up to a battery tender that's all you need to do no need to start it. So removing for catalytic converter's of course is going to create a stronger exhaust smell but it's not as bad as people make it out to be. The PCM does help in this because it reduces how rich the car is running.
