Honestly MOST of the major motor companies are also out in California. Sponsorship is kind of for a car that will be used to give the company major exposure. A race car or show car would be a good platform for them to demo products on. If it's just your daily driver then it would prove a lot more difficult to get "sponsored".
Just work on your proposal and writing skills and you have to look at it as what can you offer them. They'll return the favor with discounts on merchandise. Not always free.
2010 Hyundai Genesis Coupe 380GT
M&S Type A Front Grill
KDM 380GT Emblem
Korean Custom Wing Badge Emblem
Injen Cold Air Intake
SuperLux LED Tail Lights
O.Z. Ultraleggera 18x8F/18x9R
E&G Classics Full Aero Kit