I have a G8 V6. I believe it has 17s for the tires. I just bought the car a week ago. I live in Western Wisconsin and it recently snowed. My drive I'm was aweful today. My trunk is empty as I wanted to see how it would handle with no weight. I love driving in the snow and my previous car was an '05 Grand Prix which did good in the winter. This is my first time driving a RWD car so I'm hoping to get used to it. I need suggestions on how much weight to add in the trunk. I do not want to buy winter tires. Any suggestions?