Spannky,

I've seen clean air tests done with both having and not having an EGR system (Ontario requires this test if living in certain areas of Ontario). I've seen non EGR engines put out less junk then some EGR equipped engines with perfectly running EGR systems. The most important thing about making sure that emissions are kept to a minimum is to make sure your engine is regularly maintained, and running at maximum efficiency. Reburning exhaust gasses starves the engine of oxygen, which in turn makes the burn less complete, which in turn raises emission levels. So if you aren't lazy, and do regular PM and keep an eye on your engine, an EGR is basically an anchor designed to let you feel good about yourself. The other thing you can do is switch to biodiesel which burns slightly hotter and cleaner then standard diesel. The trade off with biodiesel is you have to either find a place that sells it, or make it yourself. A small price to pay to for less green house gasses. (Sorry for the hijack guys)