Depends on the vehicle. Both my vehicles are 4 wd so I can run all season with no problem. (Vette's asleep) If you're talking about that stagecoach you just bought, go get some winter tires asap. I'm sure the tires on it are high performance speed rated tires that will suck when cold.
I would get another Tahoe. I have an 07 LTZ and my wife loves it. I like it as well. Mine has a towing package and can pull a pretty large trailer. Gas mileage sucks on all of em.
Lambo dealers...one of the reasons I don't have a Lambo. I think I'm still smart enough to know when a Chevy dealer is pissin down my neck and tellin me it's raining.