Hi,
I actually still have the stock cats on the car. 19 years and 150,000 miles old. So I am not sure if they are actually doing anything anyway. I have a set of the Magnaflow converters that I am planning to install. (I have heard from some folks that they are crap and plug instantly ... but I have also heard they are not so bad. In any case, the bends are better.)
As far as the numbers go, I don't think you can necessarily compare apples to apples. I mean, some of the testing procedures are different from state to state, and I am not even sure they measure with the same units! But I think that knowing that the limit was 3600 and my car had 4100 gives you a sense of how far off it was. That's really only 14% too high. I see that you had 2200, but I don't know what passing is for you, or what you had before you tried those "tricks." In my case, the stuff I did reduced my NOx by 35% and had no effect on my HC and CO. So 2650 was an easy pass for me, at only 75% of the limit.
As far as the testing goes, Pennsylvania has had it for a long time. But not every county has it. Most of the ones with any significant population do, though. There used to be some air quality problems out here, largely related to the concentration of industry. But a lot of that has shut down now anyway, coal plants not included. Funny story ... my college was on a hill on the eastern edge of Ohio, overlooking West Virginia. While I was there, the EPA installed an air quality monitoring station next to my dorm! People from other states, especially west coast, used to cry about the air pollution all the time. But it never bothered me, I have to say. There were a few things that worried me, though ... particularly the fact that on certain nights, the dew would trap emissions from the steel plant across the river. So when you walked through it before the sun came up, it would turn your sneakers orange. No lie.