I like writing about people in entertainment social circles. That means I have to know about what kinds of cars they drive. Give them exotic toys to play with, and know what kinds of extras are optional, or can be bought for them. For instance, if my hero has a Ferrari, need to have it tricked out with options that are exclusive to that type of car.
Of course, if I should ever be so lucky to own a car like a Maserati, Lamborghini, or Ferrari it would be much more important to know where I could get Ferrari parts and parts for cars like it. Those aren't the types of parts you are going to pick up at the local parts store down the street. Knowing where to get the parts can make maintenance and repairs much less painful than just hoping an American shop can find them, or have them on hand.