My STi3 (completely standard) is having a MOT tomorrow and recently had the following emission figures:
Idle: CO%=1.04, HC ppm=199, CO2%=13.60, O2%=1.38 & Lambda=1.02
2500rpm CO2%=0.68 & Lambda=1.00

I understand the MOT requires 0.3% CO. Any sugestions on the best way of achieving this figure?

thanks

MY00, decat centre and afterburner exhaust:
Idle
C0% 0.04
HC 15ppp
lambda 1.023
Thrashed it on the motorway for 20 minutes before!!