Changing the tyres will make a lot of difference. I'm currently running a Honda HRV that came on 205/55 R17 Michelin Primacy 3s and was okay. Then, expecting snow, I blagged a set of Michelin Cross Climate all weather tyres the same size. The difference is unexpected and remarkable. The car rides more softly, more smoothly and more quietly. You're on quite possible the worst combination of tyres and suspension for comfort, but to improve matters on an X1 you could probably go down to 17" wheels with non runflat Cross Climates as on my HRV. Otherwise, it's a matter of swapping the car for one that prioritises ride over handling. Maybe a new Mercedes C Class on £900 optional air ride suspension, 16" wheels and 205/60 R16 tyres running at 30PSI. Not an A Class or a B Class. Not an Audi on anything more ambitions than 16" wheels with 205/55 R16 tyres. Not any BMW. ven an F30 BMW on ED spec 205/60 R16s doesn't ride brilliantly. Possibly a Mazda 3 or a Mazda 6 on 17" wheels with 55 profile tyres.

See also: Honest John Car Chooser
www.honestjohn.co.uk/chooser/