Iâm slowly building up my engine for a circa 400bhp build and its getting there but there are a few things i cant seem to bottom out so im hoping someone can help. My S3 is (was) an APY so has the narrowband ECU. I know for mapping purposes its easiest to go wideband AMK/BAM, and add the wideband lambda sensor and appropriate wiring, but most people i've seen do the conversion choose not to use the EGT sensor â any reason why ? It seems easy to me to add a boss to the downpipe for the sensor, or is it that adding the wiring is a pain ? Anyone done the conversion on here ? Most of the online guides have pics missing which is a shame. Im pretty competant with electrics (wired up a Motec in my last car) so should be easy ! Also i have 630cc injectors so whats the concencous on uprating the fuel pump, and what are the options? Opinions vary widly it seems.