My X1 M Sport came with 18" runflat which was quite harsh riding, so first I swapped them out for 18" Continental DWS non-runflats. The ride difference was quite noticeable... we also have another X1 with 17" runflats and now the ride of the two cars are almost identical.
As I like mods, I then upgraded the wheels to 19" wheels with non runflat Conti DWS. Now the ride is back to where the 18" runflats are...but still a bit softer than runflats. So I think if you switch to Conti DWS non-runflats or some other good tires you will be very happy. I just carry a tire compressor and I don't worry too much about getting flats sincwe we have road assistance anyways.