I was going to post my own alda question, but I guess I will just chime in here, hope you all don't mind the intrustion. (83 300sd)

I went to adjust my alda, but I found it was turned all the way CCW already, it would not budge anymore. I have been driving it around for some time now with not much in the way of dark exhaust, none at least that can be seen in the daytime, very little at night (headlights). Can this have a detrimental effect on the engine?
I heard also that the EGR can be blocked off to improve the performance further. Anyone have any luck there?