What year did lexus change their suspension ? My 06 rode beautifully and now my 13 rides rough?

 

Your 06 generation ended in 09. 2010 was the start of the current generation vehicle. The suspension and entire vehicle changed with each generation.

How long have you had the 13? Make sure your tire pressures are correct as indicated on the label on the driver's door frame. Over inflated tires are the major source of ride complaints.

 

The newly introduced double-wishbone suspension at the rear from 2010+ has firmed up the ride yet reduced body roll and increased cargo space from the previous generation.

Indeed I do miss the extra plushness from my 04 and 07 RX on a straight line highway cruise, but I appreciate the improved stability and handling of the my '13 RX.

 

tires are all inflated properly...I love the old suspension and will not buy another RX

 

I have no issues with the suspension of the '13 RX450h. It is tuned well for what it is. Ride is just fine with 19" rims. I even nicknamed it the "couch on wheels."
My DD is an IS300, so I am not used to a Buick-like plushness. Give it a little time to get used to it. If it is really bad, compare to a new RX on the dealer lot. Could be a strut issue, although I don't believe 13s were known for it.