Have to say not that exciting really but thought I'd post anyway. So my S3 APY comes with a narrow band ecu. Nothing wrong with it but as I'm fitting my hybrid to it though I would make my life a little easier when it comes to tuning by fitting a Wideband Ecu and Loom from a later spec S3. 2 main reason for this. 1) I wanted to, seem like a good upgrade, the cars had everything done. Why not give it a better brain... 2) WB is easier to tune. So what's involved if you want to do it yourself. Well firstly it took me about 3 hours to do, so not that time consuming and to be fair that was with a few cuppa breaks. You obviously need a complete loom from a donar S3 and an ECU to match A stanley knife, a 10mm socket, a 13mm socket and a radio to sing along to. Can't really see any point in posting a picture because it's just a bunch of wires coming out of the car and a bunch going back and you don't need to be electrically minded to do it. So there's the 2 wiring looms side by side The old is the middle 2 and the new are the outside. Basically they are indentical except for the BAM loom has a WB plug instead of the NB one. It has a EGT and extra NB plug for the rear o2 sensor. It has 1 less DPP switch and doesn't have the SAI and the Knock sensors are a little different. Other than that it's like for like. Cost wise about Â£300 for the ECU, Loom, EGT sensor, knock and WB. Not entirely it was that necessary but hey, whiled away a few hours.