AWD does not help you stop. It only helps you get going faster.
Snow tires do both.
I drive an AWD with traction control / DSC and have taken many performance driving courses including winter performance driving. All the BMW Driver Training including Mt Tremblant in the winter. The difference between all seasons and winter tires is nothing short of astonishing.
I would drive a Pontiac Sunfire in the winter with winter tires before I'd drive an X5 with xDrive and DSC with all seasons. It is THAT much difference.
The public underestimates (if they place ANY value at all on) their tires. Nothign happens with the rest of the car or driver when the tires break traction. Formula One teams can win or lose a race based solely on tire selection.
And it isn't only about snow. It is about hard frozen summer tires on cold damp roads. It is about ice. Soft, sticky winter tires are amazingly better.
And when you buy a $40k car, another $1200 for a set of winter tires is nothing. Less than the deductible of one slding off the raod into a curb.
And if you plan on putting more than 80k on your car, it will need a second set of tires. If you buy winters at the beginning, your all seasons will last almost tice as long and you will get the benefit of the winter safety.
To answer your original question... hard to beat the BMW 328xi Coupe when it comes to a cool performance car.