I have had great experience working with carsponsors.com so far and I love it! I will continue to use it as often as I can for not only upgrades for my car but also for items I can use that will be possible repairs for my van as well!
I haven't installed them yet (I work a lot and I live in Maine so its not easy to get things done in a timely fashion). But I was told that if I at least took pictures of them that I could get some cash back still.