Plenty of other reasons that people would buy the UL, but the answer in my experience is No. I had one with and one without, the air suspension does change the ride. However, you have to remember that these even at their newest year (2006) they are still 12 years old. So, I'm sure that at this point the ride differences wouldn't be huge if both cars had original suspension and average mileage.

Super easy :

Has air suspension and switches on the dash for this
Has headlight washer pop ups on front bumper
Has Radio and AC controls in back armrest
Has burnt wood trim
Has a different type of leather
Has dual pane glass
Has rear air purifer
Has rear cooler between arm rest
headliner and surrounding panels are suede

Some of the features you listed are also contained on a custom Luxury Package like headlight washers, burnt wood trim, and I believe suede headliner too. I usually look for switches in a picture of the front seat area or back seat I look for the controls in rear panel or if the rear console is folded up just look at the rear door panels. If they have memory seat switches its an UL.

People. A quick way to tell whether or not your LS430 is a UL is check the rear cabin. The centre armrest has controls for radio, heating, heated seats and massaging. Also the rear windows (including the quarter windows) have individual sun screens.

Hope this helps.

Also unless I am wrong no other trim has air suspension.

Another obvious visual is the air conditioning vents in the rear passenger area. They can be seen above the rear door in front of the exit assist handle and light. Only the UL has rear air conditioning.

Just save this link, was super helpful when I was searching, and made by a forum member as well.

As these cars are now getting older many are sold at dealers that are not familiar with the different LS packages so you will find many times they don't even fold down the center armrest to take photos of the rear seats. Another quick easy way is the memory seat switches on the rear doors. I can usually spot them in almost any for sale ad that is an UL even when the center armrest isn't folded down.