It would be hard (to almost impossible) to brick your DME/ECU by "just" coding auxiliary features.
However some common sense should be applied (ie if you don't know what the value does you may want to research
) . The F10/F30 coding threads have a lot of info in them and also the spreadsheet for the F10 has a pretty good list of known coding options and the ones which don't work.
I have not yet done anything on my F10 (just arrived in Baltmore, waiting for VPC/transit to Boston) but have done the coding on my E90s and the X5 .