Im in total agreement with the comments made by Wigwam and Landyman.
My X1 had Bridgestones fitted until most recently which have been replaced for Michellin Primacy. In my experience the road noise is always attributable to the road surface no matter what tyres you have fitted. Regarding the standard speaker set up. It is more than adequate unless you are a true audiophile or 25 year old Ibiza freek. Although admittedly, if it was a private purchase I would specify an audio upgrade as I do like my ‘Ibiza’ Club music;)
Runflats would only be fitted to the optional 19″ wheels. all other sizes are non run flats.