Current test:
HC: 3.2 Limit: 1.5
CO: 118.57 Limit: 20
NOx: 0.024 Limit: 3.5

Test from two years ago:
HC: 1.6 Limit: 2.5
CO: 15.6 Limit: 20
NOx: 0.17 Limit: 6

Looks like the limits for the HC and NOx have gotten more strict, your car two years ago would not have passed the current test if it performed exactly the same.

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2006 BMW M5 "Heidi" @ 109,000 miles
2005 MBZ C55 AMG "Lorelai" @ 165,000 miles
1991 MBZ 300E "Benzachino II" @ 165,000 miles
1990 MBZ 500SL "Shoshanna" @ 118,000 miles

(On the hunt for a good used M103 engine as of 6/10/23, PM me if you have one to sell!)