2005 Pontiac Sunfire

The cheapest mods that almost everyone starts with is a cat-back exhaust kit, headers, cold-air or ram-air intake, and an ECU chip or programmer. Don't make the mistake that so many high-school kids make, buying a cheap fart can muffler and the biggest exhaust tip they can find. Cars newer than the early 70's are designed to run optimally with some back-pressure, so removing all back-pressure will actually harm your performance. Buy a good kit from a well-known manufacturer such as Flowmaster or Magnaflow. Same with the intake. If you choose to custom-build your intake, take note of where the coolest and hottest areas under the hood are. You'll want to place the filter cone in the coolest spot possible, avoiding coolant lines and the exhaust system, and avoiding running the tubing through hot spots. A lot of people make the mistake of selecting their body kit and rims based on looks. It is best to do your research and find out which ones, if any, will boost performance in whatever your primary type of racing will be. Sometimes, the stock body is best.