The only (very slight) downside of an all-season or winter tyre on a short wheelbase car like the M3W is that there's a bit more 'give' in the tread blocks when they are new, such that the rear can move very slightly laterally on the tread blocks before the tyre overall takes up the cornering load. With such a short wheelbase this can make the steering response feel a little 'swingy', nervous and imprecise, for want of a better expression, which is sometimes interpreted as instability - learn to work with it however and it's fine in my view. As the tyre wears however, this feeling of tread-block movement diminishes. Overall I'm still happier to have a tyre that can find better grip in nasty conditions and on dubious surfaces however, than one that optimised absolute grip over everyday practicality :-)
