OK, I traded the stock 15" for a set of Cololla 14's. The tires were 175x65's, so they were a little small, BUT, I could tell the ride was slightly softer. So, after a couple weeks, I got a set of BFG Touring Radials, 195x65x14. They work out to the exact same height as the origional 185x60x15's, so speedo and odo are essentially the same as before.
The great news for me is that the ride quality is much improved. No more harshness (well, ok, not my old Buick, but much better ), and the handling is the same as far as I need.
Took a 45 mile jaunt last evening with 5 adults in the car and everyone was commenting on the ride quality and the roominess. I love it!!

Walt