Seriously considering Palisade, but undecided on model/trim. I see that the higher end vehicles have 20 in wheels, while the base model has 18 in. wheels. My golf buddy says 20 in ride rougher due to less sidewall in the tire. Is he right? If he's right, why would the rougher riding wheels go into the higher end models? I want a quieter, smoother riding vehicle. Comments, suggestions?