So, I just purchased my first BMW, a 1998 328i. I live in Michigan and I am hoping I didn't make a mistake buying a rear wheel drive car. It currently has nice all-season Auroras on it, but I have heard others say it needs dedicated winter tires. I don't have the extra cash to drop on new winter tires right now... will the all-seasons be worthless? Does added weight in the rear help at all?