What can/should i do to my '05 Scion TC?

I have a manual '05 Scion Tc that is basically all stock. What can i do to it to make it awesome? i specifically want to change the front headlights to HID's, some audio stuff like the actual stereo, and also the sound that comes out of the engine (it sounds a lot like an RC car right now). Im 17 with a part time job so i don't have allll the money in the world, but i save up pretty well. Help me out