Catalytic converter removal

I have removed the Cat on my Series 3 Spider and replaced the exhaust with a new full UK specification system (ie without a Cat). Does anyone have experience with doing the same? I read up on what the Lambda sensor does, which is to measure the percentage of oxygen in the exhaust, and fitted it to the new exhaust system. I know that cars usually only require the Lambda sensor if they have a Cat fitted, but the output from the Lambda is proportional and is fed into the main ignition ECU, so if I had simply left it off, the result would have been to richen the mixture. The car runs ok, but I'd just like to bounce this off a few of you before I put the car in for the MOT. (It did pass the MOT before, and that was with a bit of a smokey engine, since fixed, so I'm just being careful because it won't be at the same MOT garage this time, which is a shame.....)

In case any of you were wondering - My Series 3 is a US import, and hence the reason for the Cat. I do not legally need to fit a Cat over here because of the age of the car (1989). Of course, the price never came into it....!

I expect your Lambda sensor was located before the Cat, so it will operate exactly the same now as it did when the Cat was there.

Until the introduction of Euro3 specs in mid 2000 ECUs didn't monitor or care if the Cat was there or not.

I run my S3 with no sensor. Never had any problems.
Phil

Though it was in a different model, 33 IE MY 93, I replaced the CAT and the rest of the exhaust with a non Cat sports system. I ran it for 6 years and 150k km without lambda sensor without any probs.
The dealer told me that the ECU did ajust fuel mix according to the other info it got from others sensors.
Erik