Weight reduction isn't going to make an appreciable difference on a small scale, except for your unsprung weight. You remove 50lbs, you're not going to feel a huge difference. Adding heavier rims will make a difference in the negative direction, lighter rims will in a positive.
If you're going N/A, Intake-Header-Exhaust. An underdrive pulley will give you better pull in lower gears. With a lightened flywheel you will feel a big difference, but that's not cheap or easy to install. An MP3 ecu is also a must if you have a manual.
Unless you turbo, there's not huge power to be found. But, you can give the car more pep off the line, making it more fun to drive. The above suggestions will make that difference.