I think it's safe enough to lock your resistance in wattage mode, if you so desire. The firmware upgrade might be an even better choice, but basically, every time you are telling the coil it's "not" new, it goes back to the former resistance anyway, so it's kind of six of one half a dozen of the other, etc. Probably be easier to lock it (if that's an option) or do a firmware upgrade. But there isn't going to be a huge safety issue in locking a VW coil in a VW setup, IMO.
Anna