I should add, I have about 1,300 miles on my SC430 2005 model with run flats. I was expecting a lot worse and I was very worried before getting my car. To be honest, the ride is pretty good, as compared to what people are saying. It is a little rough on pot holes, nothing like the ES 2004. But it is a sporty car.
I also heard the older 430's tires would blow up as soon as they hit a pot hole. I know someone with a 430 from 03 and he had to replace those tires a bunch of times, whenever it hit a pot hole or rough edge.
Where I am from, lots of pot holes due to snow all the time (I know, why do I have a car like this when it snows so much). I hit many pot holes and the tires are just fine. I had to fill them up with about 10 seconds of air the day after it hit 5 degrees, the air pressure light went on. They looked fine, but the light said put air in it (I am told cold air does that to tires).
Anyway, the run flats are not that bad. I was strongly considering replacing them. But with a 3.5 year lease, I don't see a reason to yet.
Can't wait for it to warm up so I can drive around with the top down . I love this car.