There's no need for the winter button in the rain at all. Heck, I don't even use it in the nasty New England snow storms here in N.H.

The VX is a pretty heavy and stable vehicle and with the right set of tires, hydroplaining is minimal even at high speeds. Just don't do 60 through a puddle a foot or more deep and you'll be alright.

Winter mode is for icy (and I mean ICY) hill climbs were traction is a problem. I find that TOD will tackle just about anything out there! Winter mode will start the tranny off in 3rd gear and won't let the RPM's go above 2k (minimal tourque to reduce spinning), after you hit about 25 mph it'll shut itself off and will need to be manually set again if needed.

Power mode should be on all the time and never shut off as far as I'm concerned. There appears to be no difference in fuel economy with it on or off, just watch the heavy right foot!