The Wisper mode is done by retarding injector timing. Yes, it can be drove in this setting but probably not the best thing for extended periods. I am not sure about how this program works on a cold engine, but I can imagine the smoke (white) would be considerably thicker until things warm up a bit.
Now ...........if you were using a synthetic oil the negative effect would be substantially decreased because of the oils ability to "flow" at colder temps.
These are all just
my assumptions and the PHP crew would be better suited to answer this question.
