Intakes would be like AEM which I have and there is TRD, Fujita, Weapon R. Exhausts you have TRD, Greddy, Tanabe and I think a couple others. All the manufactures have good products and dont be fooled by the dealership wanting to install them either. My dealership was wanting over $400 just for the TRD exhaust not installed and I got it for like $314 and installed it myself in lime 20 minutes. Here is a video of an AEM Intake on a Yaris and yes it does sound like that in real life. With either of these mods it will make the car run smoother. You wont see any big gains in horsepower, but it may feel like it. I know my AEM intake came with a dyno chart showing the gains. All these two (intake and exhaust) will get rid of that restriction that is in both those stock parts from the factory and open it up a litlle more for more air to go in and come out. Any more questions just ask or you can PM me.
http://www.youtube.com/watch?v=EcKo8g4e2kI