OH dear, deiselitus has broken out again!,yes you get big fat gobs of torque from these brilliant engines, but as someone has said already they're a bit unruly in wet or Winter conditions, if there's no slip diff your right toe must have an egg under it, and yes,runflats are crap on a performance car, no compression going in to or out off corners, not confidence inspiring either, they cost a lot to replace (i pay £260 by the way EAGLE NCT5's), BMW only put them on to save weight,yet their's a space for a spacesaver!?.
If you must change the tyres i hope you hae deep pockets because the best tyre i tried were Continental Sport contact3, admittedly they were original equipment(even had M3 stamped on the tyre wall)but they gripped like someone had increased gravity to factor ten!,mileage wise i can't say because i sold it two months later.Deisel.V.Petrol,can't yet compete on mpg, but Co2 are getting towards parity, these cars?, its horses for courses, what you drive is fine.