I am very disappointed in the above method of "passing" the emissions test.
First of all nobody really likes the hassle and cost of emissions testing, it was a mandate from EPA via congress and the CAA of 1990, BUT what MADE the emissions testing happen was just such methods mentioned above, ie many polluting cars.And as I tell citizens here, if you think its an inconvenience now, how will you feel when it ( air quality) gets so bad that your kids will not know the joy of driving a vehicle, because they will no longer be allowed to own one. If you think this will never happen, think again about all the things one thought would never happen and they have indeed come to pass.
secondly, I have an 87 300E that was 80% below the allowed emissions limits for HC, 47% below for CO and 68% below for NOx. Why? proper maintenance, replacing the O2 sensor at 60K, then again at 120K, new cat at 100K.
third, I believe that there is not a way to "lean out" a 300E without really screwing it up because of CEC's.
But, at least for now it is still a relatively free country, at least in theory. Good Luck