I had a Skoda Fabia VRS with 170bhp and a LOT of torque.
I wont condone 'racing' on public roads, but it was quicker than the ST.
Thing is though, real racing (indeed the true test of a cars worth in my book) is on the track, that is where the ST Fiesta seems to be at home.
The Fabia with a big diesel (like that BMW) will undoubtebly suffer in the handling dept.
A 2.3 litre turbo diesel will easily dust a standard ST every time.
Put them both on a circuit like Croft for example, then things are slightly different then.