In one of the chapters where Naruto is learing the rasengan Jiraiya says it would be useless for Naruto to learn the hand seals. My question is, How would the rasengan change if Naruto learned and excuted the seals for it? Would it make it stronger or something? Which brings me to my next question.
What do hand seals really do? They don't seem to serve any purpose except for making the jutsu look fancy. Does it have something to do with selecting the specific jutsu?