Look, I'm sorry if my "use the search" comment came off wrong. Really.
If you want some HP (horsepower) tips, then follow the very common types of mods everyone seems to do and the general rule of thumb (get more air in and more air out).
You can get more air in easily with a Cold Air Intake. A K&N cone filter and some custom tubing and hoses made as part of a kit for our car. Cone filters generally flow more air than the flat type that comes in our stock intake. You want the air it breathes to be a cool as possible and not hot engine air, so you'll see partitions and sealed boxes tied to "ram air" ports or other plumbing to scoop outside air as you drive.
To get more air out, the common thing to do is put on a Cat-back exhaust kit, or make one custom with any combination of mufflers, resonators, and tips. Magnaflow and Borla make two nice kits for our cars. Highhorsepower.com can hook you up with all these items.
Now for FREE HP tips...well little is free, but you can make sure your tires are properly inflated and not causing a drag. You can unload some weight by removing things you don't need or don't carry a lot of excess stuff in the trunk. Who needs a spare tire anyways?
That's all I can think of for now. Again, sorry if I ruffled any feathers.