Lamda probe and AFM

[William]

When my (I now think to be) useless mechanic told me I needed a new AFM due to flat spots, I bought one from a very good zone member.When he installed it the guy told me that it was one from a non-cat prepd. engine so he had to set the fuel/air mixture manually. Given that he was also installing a new downpipe without a lambda boss, is it likely that when I get the BTB 6 branch, I will have to get a new AFM AND lambda probe, or will he have tied it up somewhere, what's the most common thing to do?

Also, the AFM part numbers matched perfectly with the old one, so how is it that they are for different engines?

[kam-325i]

AFAIK, i makes no diffenerce. there is no such thing as a AFM for a CAT equipped car, they are all the same....
If the Lamda sensor is telling the ECU the exhuast is to rich or to lean, the ECU adjusts the timmimgs for the injectors..no the AFM