I got my 2.0 Roadster (08 reg) a couple of months ago, having driven two others before deciding on the one I bought. The first had ordinary tyres and was fine, the second I had was fitted with run flats, I told the dealer I liked the car but the steering was awful (tramlining) and told him I thought it had a problem. The third I tried was also fitted with run flats and steered exactly the same as the other one, so to me it was clear it was the tyres. I decided to buy the car anyway, and will stay with the run flats till they are worn. I have got used to them, and to some extent i feel that it makes the car more of an older pre power steefing car, like one of my old Spitfires, and in a way adds to the enjoyment of driving because you are never sure which way they are going to turn! It's called tramlining for a reason, and it sure feels that way, and certainly different to what you would expect on a modern car, but if you really dont like it and want something more reassuring steering wise, than you will probably have to change them. Hope that info helps a bit, good luck.
