I don't worry about it. As long as I have been coding, 9 months now, I always code my car, and I have coded probably 50 others, all with the car on and the engine fully running (EXCEPT if I am coding the DME module).
I have never had any issue with coding and excess noise, and I do not have to worry about proper voltage being maintained on the car, plus I get the added benefit of active HVAC.
IMHO there is nothing worse than inadequate voltage during coding, and it is a much greater threat than noise introduced by the engine.
- 2011 535i M-Sport (Born 10/10) - AW/BLK/DW - /ZMP (w/ARS, EDC, DHP, & AD) /ZPP /ZP2 (w/ZPS & ZPT) /ZCV (w/SCAD) /6FL /6VC
- Mods - 2TB SAT / 6WB MFID Cluster / 4U1 Ceramic Controls / 6NR BMW Apps / Rear Fog Lights / Cyba Double Layer Black Chrome Quad Tips