I've got Continentals all round on my Z4MR. I must admit I'm a novice when it comes to tyres - is there a "best" option for this car or is it either/or between brands like Continental, Bridgestone, Michelin, etc? I'm just curious if you're already spending around £150/200 per tyre, is it worth spending that little bit extra for the premium model.. what are your experiences going from one brand to another?