Tried it in the Cooper for a bit of a giggle
Heavy Convertible (roof up to aid aerodynamics), Full tank of fuel (filled up 10 minutes previous), Tesco 99 (The Minxs' usual diet), sat at a steady 30 and floored it. Wheels are 215/40/R17 run at 35psi....Did two runs up and down the same dual carriageway and were in 0.2s of each other.
Average = 9.2s