A diesel with a CAT has a higher carbon foot print than one without. The catalytic converter finishes burning any unburnt hydrocarbons left in the exhaust, thus adding more CO2 to the atmosphere. Removing the CAT also makes the smell from biodiesel burning drivers much less offensive. I don't see how having a cat or not can change the driving habits of a given person. Learn some physics, then bash the modifiers.

I believe the discipline you were going for was Chemistry, not Physics.

and guess your 2500 has a real nifty 8" exhaust tip too

...Over the last two millennia, physics had been considered synonymous with philosophy, chemistry, and certain branches of mathematics and biology, but during the Scientific Revolution in the 16th century, it emerged to become a unique modern science in its own right.[6] However, in some subject areas such as in mathematical physics and quantum chemistry, the boundaries of physics remain difficult to distinguish...