I am slowly getting into the same thing... Injen makes a good cold air intake that isn't too horribly pricey, but you probably shouldn't get a short air intake because your going to pull hot air from your engine. Walker and Bosal make after market mufflers for corollas that are a lot better than the stock and fit right into the bolts for your existing exhaust manifold. Should give a better sound, but wont sound like and angry bumble bee.