(disclaimer; we sell what you are looking for)
basically, you need a RESISTOR to get the new LED's to flash at the correct speed, so you would need a resistor for each indicator, etc.
Cannot think of any negative effect on the CANBUS or other system, we sell a good few conversion kits, without adverse feedback, etc.
Cheers
Chris
Depending on model year and if you are using the OEM BMW LEDs you may not need a resistor at all.
However you might need to have it "enabled" in the software which would require a BMW dealer to do so.
It's a 2007 GS and would be using original BMW LED indicators.
Will have a word withShane later in the week as well.