Boy, that's one happy looking car, isn't it? The teeth are from Auto Expressions. The car is a 1992 Mazda Miata, and I highly recommend them if you have the means.
I've upgraded the factory stereo a bit (loud techno music makes a good performance upgrade for any car), replacing the head unit with a RioCar Linux-based MP3 player, and added a 5-channel amplifier and speakers from PPI and a T52 subwoofer from Bazooka. The end result is that I effectively have an intelligent multi-hundred-disc CD changer that sounds great even with the top down, and takes up essentially no space. I couldn't be happier with it.
I also added an alarm system, because I'd like to keep all that stuff. I got mine from Wolf Miata, and I recommend them highly. Their products are great, and the service is absolutely unbeatable.
See here for info about my previous car.