Gibby is on the right rack. In order to get sponsorships you either have to know someone from the company you are wanting to sponsor you or you put tons of time, money, and effort into your car to get yourself noticed. Street racing will not get you noticed and will not get you sponsorships. While tuner companies certainly make a pretty penny off street racers they aren't going to openly sponsor one because it can cast negative light on their company. Companies also want to promote motivated, high knowledgeable, and respectable tuners. Not some guy off the street with a big attitude, who races anything that moves, and doesn't know much about his or other cars.
I'll leave you with this personal experience on sponsorship. My two friends and I have co founded our own racing team. Now don't take that wrongly, we are not some high budget, take the world by storm, and travel the country racing crew. We are three friends that love cars, racing, and wrenching with each other. Over the last two + years we have taken a junk yard special Camaro SS and made it into a high 9 second beast. We are all the things I previously mentioned that companies are looking to sponsor and yet we still have no major sponsors. What we do have is free dyno time at a local shop in turn for putting their name on the car, we also got a nice discount at the trailer place for again putting their name on the car. To get those we knew the owners of both places and still had to beg them. So here we are a bunch of shade tree mechanics who are now out running the same times as the big shops in the area and still no sponsors.
Now ask yourself, what have you done to your car, for the cobalt community, and to prove yourself worthy of sponsorship that a tuning company would even look your way? What have you done different or to prove yourself?
The last thing you have to consider is that sponsorships are business deals. This means you have to have a business plan, goals, a resume, and all the other things it takes to land a big business deal. You need to prove to a company that they can make money off you, that you will sell their product. This will also take a huge effort on your part. If you get sponsored there will be show requirement, track day requirements, and meetings. Are you prepared for this? If you get a sponsorship you can basically say goodbye to every weekend from April 1 to November 1.
In summary, sponsorships require ALOT of work on your part. Good luck, and I hope you get one. It's possible, but not probably, but go out there and prove yourself and work your tail off and it might just happen.