2006 Toyota Corolla, Trying to add speed and tune up

To keep busy for a couple hours on a light budget: Get a high flow drop in air filter or a short ram / cold air intake. Replacing old plugs might give it a bit of pep, but don't buy into the "qaud post" crap. Regular old NGKs should work just fine IF your plugs even need replacement. Running seafoam through your intake might clean up your intake system a bit and it creates gigantic plumes of smoke which is fun: (MAKE SURE you are in a well ventilated area: for your Toyota, find the small air tube that connects to roughly the same area [intake manifold] as your air intake and disconnect it at the end connected to the plastic splitter, when disconnected the engine will idle rough, and the tube *should be sucking air in*. put about 1/3-1/2 of the can in that way like a straw, the engine will rev higher. Once the drinking is done, Cut the engine, and let it soak for like 10-15 minutes. Prepare for the smoke show. Start the engine and you will see a significant amount of smoke. If you see a lot, revving the engine a few times will loosen and burn off a ton of intake residue and generally irritate your neighbors with giant clouds of smoke. The smoke should stop completely after about 2-20 minutes depending on how dirty the intake is.) I used to have a matrix and cosmoracing.com has a good deal shipped on the cold air intake (CAI). If you don't want to worry about "dipping the straw" and sucking water into your engine, go for their short ram (SRI). They both improve airflow into the engine and the output difference is negligible. The intake chatter does add a nice growl to the engine noise though. Next look at replacing the ECU, exhaust, hi-flow cats and headers if you have the $$. Some people add turbos, but really unless you do the work yourself, you might as well start with a different car or swap your engine (XRS should fit with the least trouble). Forums have a ton more information than me, or this place. Have fun!