I went to home depot awhile ago and I bought these bulbs in the outdoor lighting section that are the 12 v wedge bulbs and 18 watts. I put them in the doors and the trunk and it is so much better its great. heres the bulb I got, they were cheap too. In the trunk i just unhinged that little plastic cage thing that the bulb goes in and clipped it off.
http://www.asihome.com/ASIshop/product_info.php?products_id=1802
http://www.asihome.com/ASIshop/product_info.php?products_id=1802