iirc, you don’t even have your license yet, correct? If I were you, unless I am going to keep the bike forever or track/race it, I wouldn’t spend money on it other than fuel, maintenance and tires. If you are new to the whole motorcycle thing and unless you already know everything there is to know about riding, you will have more fun getting and reading a $12 book on performance riding than a $200 muffler.
If you wanna go fast, spend the money and learn how to ride fast instead. The skill you acquired will be with you forever no matter what bike you are on. :thumbup