We had a KW T2000 and it was bad about the wind blowing through the little gaps in the door to cab construction. It also blew through the gap between the window and door handles. You could turn the heat on full blast on a cold Indiana day (temps in the teens) and you would still have to have a long sleeve shirt on to stay comfortable. I have not driven a 387 yet, but I hear that they are slightly better about this that the T2000.