Hello Robert,
Have had the BMW 740i and now an LS 400 with DHP. The DHP gives a much harder ride where the roads are not good. Further there is less travel on the suspension. The only stadard tyre that fits is a Pirelli assymetric. So, you get a harder sharper feel but trade off that limousine ride. All down to personal choice. For me I will like the ride of the BMW 740 on the Lexus as I prefer the smoother ride. Next best thing for smooth ride is the standard LS with the advantage of having a wide choice of tyres.
Lukas :D