I have NCS Expert set up along with INPA/DIS, etc. I've made changes to my e36, e39 & e63 & many other cars for friends & members of my local forum. It's actually quite easy once you go through the process a few times. I've even remotely logged in to another forum member's laptop to make a few changes for him. Obviously to do that the software & cables have to be in place.
As for coding bad info? Well if it is really bad the software goes into a fail safe mode & just writes the default build for that module if it detects bad code or blank code. You can cause issues with comms in the car if power dies in the laptop, but writ g a default code clears that up.
I would love to have AE as DRL but I think this option is only possible in LCI models. You should ask your friend to also program Welcome Lights.", you can choose which lights you want on when you unlock your car, this is Different from HomeLights (which can also be coded to work remotely with trunk release button on the key fob, see mine below). Welcome lights are only possible on LCI models too, Homelights work on both pre & post LCI cars.
There's loads of other things to code on e63/e60 like:
- Digital Speedo
- Comfort Eject for Key (no need to press key in to remove it)
- Acoustic acknowledge on lock/unlock
- Heated seat function display in iDrive
- Enable Aux port in iDrive for retrofit
- Enable iPod retrofit
- Autofold mirrors (where fitted) controlled via remote fob
- Rain close the sunroof
- Roll up/down windows from remote fob (enabled as standard on European models)
Probably a few I have forgotten about.