Got new diesel exhaust with no catalytic converter: Is it much worse for the environment?

I've got a 2006 Silverado 2500HD with the Duramax 6.6L diesel. I recently upgraded to a turbo-back exhaust system, which apparently has no catalytic converter. Where I am this is legal, but I know the converters are there for a reason. How much of a difference do they really make? Should I feel really guilty about destroying the environment and switch back to stock exhaust?|||If you are concerned about the environment you wouldn't be driving a truck anyways, or a diesel one at that. Don't worry about it, because that exhaust probably made your truck more fuel efficient. Burning less fuel is the best way to reduce emissions.|||Diesels don't ever have catalytic converters thats why they are more fuel efficient. diesels engines are made to produce more torque at slower rpms the cat converter makes that hard to do. The converter uses energy from the engine to heat exhause gases over 1500 degrees. diesels burn much cooler and don't emit the same pollutants as gasoline. thats why there is no need for them to have cat converters.|||i would feel bad. did u know that most big rigs that are out there on the roads all day and night don't have catalytic converters.