just had a look at my z4 ecu today and i have noticed that i have a extra chip on my ecu, does the normal z4 ecu only have three chip's like the picture below? as i have a chip in the box i have highlighted below.

 

Yes it does fella, the un-chipped Z4 looks just like the pic.

 

bonus just need to find out what chip i have fitted now,

 

post a pic up for us to have a look im sure one of us may recognise it.